I frequently got problem with (usually related with each other):
1. When I open Adobe Acrobat Pro 7 or Adobe Photoshop CS2 that I don't have administrative privilege to run the program after awhile
2. "The windows installer service could not be accessed" error when I install/update a program in windows XP
both 1 & 2 problem can be corrected when I did:
a. Run> cmd > msiexec.exe /unregister > msiexec.exe /regserver > restart.
b. Run AdwCleaner program search and clean, reboot.
I have Avira virus (complete check daily) and Malwarebytes anti-malware (pro). Right now I run complete check with Dr.Web.
I don't wish to uninstall both Adobe programs because I don't have the original CD anymore ...