At the risk of being flamed by those with "superior knowledge", would downloading Hiren's Boot CD and burning it to cd or copying it to a usb stick, followed by booting the puter with said cd/usb stick and then selecting "minixp" be an idea? Once in MiniXP you can install and run things like MBAM, etc, meaning you can scan your machine and rid it of nasties.
It's a trick I've used several times on other people's machines.