Hi Kroenig
I think that "Support" thought (as I did) that you were talking about SD with Antivirus, which has a "Tools" menu,
not PC Tools Antivirus Free Edition (PCTAV), which doesn't.
Re: PCTAV problems (I know first two are obvious but you can never assume anything.)
1/. Did you download PCTAV from:
http://www.pctools.com/free-antivirus/ ?
2/. Have you changed any settings from the defaults?
3/. Are you sure there are no other active (or even incompletely uninstalled) AV or other security software running concurrently?
PCTAV Free is certainly not trouble-free but I've been happily using it on 2 XP-Pro machines since January with only minor issues, nothing like the catastrophe you've described.
Pete