user32 DLL Error

I'm runnung NT 4 server, and just recently when I run any application, IE, Backup exec, watchguard utility, etc... I would get an equivalent DLL error, depending what I'm trying to launch, that points to the user32DLL, eg. opening IE: I get "iexplorer.dll initialization failed." in the body, the error states: "the dynamic link library c:\winnt\system32\user32.dll initialization failed.". All the errors I get points back to user32.dll. I reboot and am able to launch explorer,etc.. for a period of time, but always reverts back to that error and am unable to launch any more application. i've increased the heap size as microsoft suggested on knowledgebase and reapplied the sp6, but after time, a day, two days, I get the same error again. The only thing I did prior to these errors is updating to the visual basic sp to maintain my visual sourcesafe database.