windows cannot find programs

windows ME cannot find programs like excel, word, outlook, etc. However,can go to the command prompt, use IE, and some other things. Cannot open up regedit or msconfig. Booting up in safe mode does not change a thing. I suspect it is a virus. Has anybody seen this? The exact message says, “Windows cannot find c:\program files\whatever\word.exe (just an example). You must have mistyped the name in the Run dialog.” ANyways, something to that effect… Please, no stupid comments about reloading Windows.
BTW, can browse in the explorer and find the executables for all programs that run. Help!!!