Manufacturer's Recovery and Restore Systems.
Most pre-configured store bought PCs will already be dual or even triple-boot and so installing another operating system may not be as simple as we may have thought.
Determine what you have.
When PC manufacturers configure and partition their machines and install Windows and add their recovery system it is usually with little thought or regard to anyone who might come after them with a view to installing a second operating system. Some factory setups can turn out so convoluted that they will all but exclude any possibility of making even the simplest of changes. It must be our mantra therefore that before we attempt any tinkering with a pre-configured machine we should study what we have, so that we can determine what we can and cannot do.
Reconfiguring any pre-existing system is almost invariably going to be problematic and time consuming and so it may in the long term be easier and quicker to simply start afresh with a cleaned or replaced hard drive. Before messing with any existing drive that contains something you'd rather not lose you must have full backups of data and operating system and possess the ability to restore them. If you are not so prepared then you are being foolhardy.
If you are capable of backing-up and restoring your operating system then you are already more than half way towards being able to begin with a clean drive, because it does not take much more to be able to transfer an operating system to another hard drive or to a partition of your choice on a newly cleaned and repartitioned drive.
Too Easily Broken.
You should never rely on a computer's on-board recovery system to get you out of trouble because even small modifications to some machines can render the recovery system either unable to start, or cause it to stall when it does not see the exact hard drive configuration it was expecting. The only way to reasonably expect a recovery system to still work on a machine that has been altered is if that recovery system can be run entirely from removable media such as CD/DVD or USB/SD flash device. When run in this manner however there is a possibility that it will be programmed to do a complete factory reset, which will not only delete all personal data but also any new partitions or operating systems that may have been added.
Take a Chance, or Take Control.
If after hard drive changes a machine's on-board recovery system still works then it may indeed replace only the Windows install while leaving any new partitions and their contents in place. It is even possible that it could work with no complaint on a resized or a moved Windows partition, but you would have to carry out extensive tests of your own particular system to confirm this before ever trusting it would only do exactly what you wanted. There is such huge variation in recovery systems across different PC makes and models that nobody could ever hope to provide a single reliable guide. The time required to learn an on-board recovery system and understand the probable outcome of its automatic restore process, would be far better spent in mastering a fully controllable third-party cloning or imaging solution that can be used on any PC.
Boot Managers and Boot Records.
There are a couple of different startup methods that an onboard recovery system might use. A common one during the XP era was a custom MBR (Master Boot Record) which after the press of a specific key during early bootup would divert the normal boot process and instead of loading the operating system would target and start the recovery software. Any change to a custom MBR made by installing a different bootmanager or by an install or re-install of Windows or Linux, would render the recovery system unavailable by normal means.
With the introduction of Vista the custom MBR was discouraged in favor of using Windows own new style bootmanager to start recovery. As before the press of a key during early bootup would halt the normal boot sequence and most likely bring up a boot-menu where the manufacturer's recovery could be selected. Any changes to the bootmanager or to the exact partition placement that the new Windows bootmanager requires to operate correctly has the potential to not only prevent access to Windows but also the recovery system. A true double whammy.
There was a certain amount of cross-over of these recovery startup methods after Vista was released. Some manufacturers were slow to adopt the new way and continued on for a time with a custom MBR. Others embraced the new way from the beginning and when Vista became unpopular and they returned to supplying XP on their machines they retained the new Vista bootmanager in a kind of hybrid XP-Vista boot method. So if you have a pre-installed XP or Vista machine from around 2007-2008 then you could have either of these recovery startup methods.
If you are intent on making changes to an existing system and have disaster recovery plans formulated and tested, then you can look at making some space for a new partition. This may be easy or next to impossible to do depending on a machine's current partition arrangement. A degree of knowledge will be required on the subject of hard drive partitions and of the limits and conventions of the partitioning style that the drive is configured with. There is little point in making space for a new partition if the limits of the system won't allow another partition. A Beginners Introduction to Partitions.
There are of course a myriad of other factors to be considered before attempting to make alterations to a pre-configured or store-bought machine and we strongly suggest that you have a look at our Various Variables list and indeed give consideration to all of the advice and warnings we detail on that page. There is also now a new partitioning style being used on most Windows-8 supplied machines that has different limits and conventions to the long standing MBR partitioning style. The GUID Partition Table (GPT) has new rules and limits and so the factory recovery systems and partition layouts on these latest machines may vary greatly from what you see on this page. If we have convinced you to exercise some caution then you may want to begin by trying out some of the other ways to multiboot that do not require making fundamental changes to hard drives or partitions. Safe Ways to Get Started With Multibooting
MBR or GPT - UEFI or BIOS
We hope the following examples will demonstrate that no quick-guide can possibly cover all the angles and that you really should follow our safe working suggestions. In each of these examples the main image shows a hard drive seen from the Windows-7 Disk Management utility. Note that this Microsoft utility does not correctly read non-standard Windows partitions and reports them as having no data on them. The thumbnails will show you the same drive as viewed from third-party partitioning tools. (Hover over the thumbnails to replace the main image. In most browsers clicking the thumbnail will freeze replacement image. Click off images to remove).
Resizing the C: or E: partition to make space for another OS would be perfectly possible here, however any new install of a Windows operating system will replace the MBR with a stock Microsoft version, so you would loose access to the recovery system unless you knew how to restore the custom MBR, or you were using a third-party bootmanager that was capable of starting the recovery process as well as the operating systems. Resizing the Windows partition may cause the recovery system to fail to function correctly, or it may still work and restore not only Windows but the partition to its original size. A resized E: partition and a new partition and operating system may survive a run of the recovery system, but the bootmanager, whether third-party or Windows own, will require repairing or reinstalling.
All 4 possible primary partitions already exist on this drive so you would need to change one to an extended partition, inside of which a large number of logical partitions can be created. Once a suitable logical exists and if there is no custom MBR then an install of a later version of Windows from the one that is already present may auto configure dual-boot for you and still retain a working recovery system, using it however would restore the original configuration of the Windows bootmanager, so removing added boot options. If there is no custom MBR then a third party bootmanager or even an install of Linux and GRUB to the MBR may still not break the recovery system, which could still be started by way of the Windows F8 bootmenu. Using recovery however may replace the MBR with a Windows stock version.
The only way here to create another partition and perhaps retain everything would be to resize the Windows partition down and then expand the extended partition into the released space. You could then make one or more logicals for operating systems or data. If there was a custom MBR involved then the Media partition would probably have to be moved to the start of the new extended partition and so remain the 4th partition on the hard drive. Any install of Windows would of course over-write the custom MBR so you would need to be able to restore it. If the Media partition is being booted through the Windows7 or Vista bootmanager then the exact starting sector of the partition could not be moved without also updating the boot configuration data (BCD) that the bootmanager uses.
This type of setup is a minefield and you should do extensive research on your particular make and model of PC to see if other people have written up their experiences. On some Dell systems the media partition was a super hidden and all but invisible 4th or even 5th partition, which made any attempts at partition changes risky to say the least.
See Dan Goodell’s excellent work on the Dell MediaDirect partition and recovery systems.
Relatively easy here to resize the Windows partition and create another primary and/or an extended for one or more logical partitions. As long as the MBR is indeed a stock Microsoft one then installing another Windows OS of the same or later vintage to the one already present will auto configure dualboot while retaining a functioning recovery system, although using it will likely remove your boot option for the new OS. Installing an earlier Windows version will not configure dualboot but will leave you with just the new OS, so you will need to know how to manually reconfigure the Windows bootmanager to get that dualboot. A Linux install that is allowed to put GRUB in the MBR may correctly auto configure dualboot while retaining a functioning recovery system, but using recovery may replace the Windows MBR and so make Linux unbootable until you reinstalled Grub, which is a task often beyond many Windows users.
Factory Installed Lightweight Operating Systems
Safe Ways to Get Started With Multibooting
Is a Drive Configured for MBR or GUID Partitions?
BIOS or UEFI - (Unified Extensible Firmware Interface)
WinRE - (Windows Recovery Environment)
Limits to the Windows Disk Management Tool
Dan Goodell on the Dell MediaDirect Partition
Wikipedia on Dell's MediaDirect
A Visual Guide to Understanding the Boot Sequence
A Beginners Introduction to Partitions
The Windows System and Boot Partitions
The Win-7 System Reserved partition
Using the Windows Disk Management Utility
The Windows Boot Files - bootmgr and BCD
Advice and Warnings and Things to Know