|It's probably not a registry thing so scanreg/restore lilkely won't fix it.|
What did you do to it between the last time it worked OK and the first time it didn't?
Post back contents of your config.sys and autoexec.bat. From the c:\> prompt type type config.sys and enter. Then write down what shows on the screen. Then
type autoexec.bat and enter.
Real men don't use AntiVirus; they just reformat