Progams will not start on reboot in XP pro

[Jewison]

I have a problem that started yesterday. I tried to log onto my account on my home computer. It did log on but the antivirus, AdWatch, and other program that usually load didn.t. The only thing that was running was the clock in the taskbar. When I rried to click on the icon it would say failed to find the file associated with this program...or something like that. I did a full virus scan and adware scan on Trend Micro and found nothing. I can surf the net and check my e-mail but nothing else will open or load without giving the error message above. I have not loaded any new programs lately. Any ideas as to what is wrong. I also tried to go into msconfig in the Run menu and it would not work and said can't find file msconfig.exe. Please help...