Backing out of a failed Win7 installation

How do I back out of a failed Win7 install attempt? I started a Win7 installation on an XP system and some files were installed on my c:\ drive that force me to chose between proceeding with the Win7 install or using XP. Because of the error messages that the Win7 install generates, I'd like to back out of the failed Win7 install and start over from scratch after making the XP configuration less complicated.

Is there any way to manually delete the Win7 pre-install files so I revert to a purely XP system configuration? I've been around since IBM PC-2 and MS-DOS days so I am more than familiar old fashioned, one-at-a-time file deletions, if that is what it takes. The question is what files should I delete?

Alternatively, I have noted that in the 'Program Files' folder on my C: drive, there is new sub-folder titled 'Microsoft Windows 7 Upgrade Advisor'. Presumably this entire sub-folder and its contents can be deleted. I also noted that what I think is this same sub-folder is listed in the 'add or remove programs ...' section of Control Panel. Would removing this sub-folder with Control Panel accomplish what I am trying to achieve?

If I am off on the wrong track, any and all advice on how to temporarily get back to my purely XP configuration would be deeply appreciated as I am no Windows expert. Thanks, in advance.


I do not believe you can "get back" a fully intact XP, now. As for starting from scratch... when you put the Win7 DVD in to install, it will format the drive before continuing to do the install.

No, the Upgrade Advisor is a utility that shows how well a machine will take Win7, degree of compatibility. Does it have enough space, RAM, driver issues, etc.

Depending how far your "failed attempt" went, you may currently be standing in 'no man's land'; w/out an intact XP & w/out a completed Win7.

Just start over, it will format & do a clean install. Unless the Upgrade Advisor will run, 1st.

Win8Logo (2013_02_06 10_30_24 UTC).jpg

Drew -- Thanks so much for your response. What I think you have accidentally told me is why my initial attempt attempt to install Win7 failed. By habit, I partition my hard drives into rather small partitions to both facilitate backups and to keep any malware or viruses from writing unwanted files of any size into the partition. It is not a foolproof solution by any means but over the past twenty years or so it has saved me a lot of trouble several times.

Back to my original issue: I hadn't known that Win7 would try to reformat my hard drive. I am aware that one can not go from XP to Win7 directly. Probably because there wasn't much free space in the partition where my XP OS is located, I think all it managed to do was install the Windows 7 Boot Manager. When I start the computer, it shows the usual BIOS screens and immediately goes to the Win7 boot manager screen. This screen asks me to select between:
-- Earlier version of Windows
-- Windows setup
Also, down at the bottom of the boot manager screen, there is also a 'Tools' item called 'Windows Memory Diagnostics'

If I do nothing, the PC defaults to 'Windows setup', stalls, and lists several error codes. If I select 'Earlier version of Windows', the PC boots to XP normally and everything functions as it used to. In addition, all Windows XP updates install properly. A file-by-file examination of the OS folders didn't show me anything that looked new or unusual but maybe that is because I didn't know what I was looking for. Accordingly (and I should have made it clearer when I stated my problem), what I am trying to ask is 1) how do I identify these boot manager files and 2) what is the best way to remove them. My guess is that if I can get rid of the Win7 boot manager, my machine will return to its original state. You may ask why not just try to proceed with the Win7 installation? For a bunch of personal reasons, I just don't want to do that just yet as I am trying to deal with several other deadlines much more urgent and important at the moment than the Win7 conversion as I recognize I may have to a clean Win7 install and reinstall everything.

Again, thanks in advance from any advice or suggestions from anybody. I started with MS-DOS but don't pretend to know much about any Windows OS after Win98SE.


Excellent Member
Microsoft Community Contributor
As Drew mentions, not knowing exactly where you were in the install makes it hard to recommend something that will not have a possibility of making your system unbootable. So I would continue to use the Prior OS boot to make your deadlines and run the Upgrade Advisor to see what it says.

After making the changes from the Upgrade Advisor, then try the Windows 7 install again, and from the beginning if necessary.

But currently your system is probably set to use the Windows 7 boot scenario. This part starts in the Master Boot record on the drive and instead of using the XP ntldr, it looks for a Windows 7 bootmgr. There is a command to change it back to XP, but I cannot guarantee it would work in your case. Let us know if you want to try the bootsect.exe command.

Check the links to see if anything helps.

How to uninstall Windows 7

Bootsect Command-Line Options

Saltgrass -- I can not thank you enough for your note. You have provided me with the information I didn't realize I was looking for. Obviously, what I was trying to do is more complicated than I had recognized. Because of both travel and a heavy work load, I am going to postpone sorting this problem out for a couple of months. Besides, I need to fully understand the two references you so kindly provided. I will revisit the situation when I have more time and have a better backup of what is on this PC. In the interim, the 'Prior OS Boot' is tolerable, even if somewhat clumsy. Thank you again.

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