Uninstalling Windows SP1

When trying to open many programs I have installed the following messages come up "Fatal Error: Unable to load jit Compiler: (mscorjit): file may be missing or corrupt. Please check or rerun setup."
And another. "psexec.exe-Bad Image: C:\Windows\system32\srvcli.dll is either not designed to run on Windows or it contains an error. Try installing the program again using the original installation media or contact your system administrator or the software vendor for support."

My computer is a desktop with the following specs: Windows 7 Ultimate 64 bit, HAF 932, 850W PSU, X58 chipset, i7-920, 12GB DDR3-1600MHz

I use this computer mainly to run Microsoft Flight Simulator (FSX) which is running without problems, the issues I'm having are the programs that I use to run with FSX like live weather, ATC, and others, will not start and show the same or similar message as above.

I understand a repair install to fix the Windows 7 operating system without reformatting can be achieved from the desk top using my Windows7 Ultimate installation disk. This I believe involves Uninstalling SP1, when I try to do this a message comes up "Windows Update. An error has occurred. Not all of the updates were successfully uninstalled." Any help with this problem will be appreciated.

Better to use the latest official Win7 installer with SP1, which you'd need for repairs or reinstall anyway. It's provided in the Information box in Repair Install.

Look over these steps as well to see how close you are to getting and maintaining a perfect Clean Reinstall which are same for retail.

Thanks gregrocker, took your advise and downloaded the latest Windows 7 installer with SP1 and performed a repair install from the desk top. Pleased to report all problems fixed

Glad to hear it! Good work

If that's the original factory preinstall you can gain back some of Win7's native performance from the corrupting bloatware by following these steps to Clean Up Factory Bloatware especially establishing a clean boot, uninstalling junk you don't use, checking System Files, cleaning and defragging.

When the time comes treat yourself to a Clean Reinstall - Factory OEM Windows 7 to enjoy pure Win7 native performance. Once it's set up save a backup image to use in place of Acer Recovery so you never have to reinstall again.

We'll be here to help you.

Many thanks again Greg, that link to the latest official Windows 7 installer with SP1 saved me from many hours of reinstalling various programs that are used in FSX, over 25GB worth! I was delighted when at the end everything was repaired and all my FSX addons worked again. I have the official Windows 7 installer with SP1 on a DVD in a safe place, ready for the next time.

PS Passed all information re this repair install to another FSX user who was having similar problems. He has had the same successful result......Where would we be without forums.