if you told us what your O/S is.
that said you sound like you have somehow lost your Reg.exe file.
post back with the required information and we can help.....
I think that I have a virus. I can't get my programs to run. I haven't lost any files fortunately, but whenever I try to open a program the hourglass goes for a minute and then nothing happens. I can't run antivirus programs either. The only thing that works is internet explorer. I don't know what to do... Any ideas???