http://housecall.trendmicro.com/

That is a link to trendmicro's online virus scanner.

I have used it before on a client's PC.

I've always been weary about stuff like this though... cause you are giving them access to scan, analyze and modify (if virus is found) files on your computer.

What is stopping them from finding something of interest... and xfering it to them while they are providing you with a free* service?

There, you see what this site does to people?! It makes them parinoid! At least me, anyways...