>>I have a big problem. All my files with extension .SCT
>>(corresponding of all .SCX) are replaced by .VBS files
>>with same name of each form. Virus is named VBS.Plan.B
>>(VB script virus).
>>
>>Someone knows how to replace my old .SCT
>
>Backup. That's the only way.

Or, if you have a compiled .APP or .EXE, you can use ReFox to recover your forms.

Yet another reason to use SourceSafe...