It's unfortunate but most antivirus software is fooled by these things. Try the following and if it wont work in regular mode, try it all in 'Safe Mode with Networking' which is #2 on the menu reached when you tap F8 repeaedtly on startup.
Download, install and UPDATE (very important), the FREE version of THIS tool.
Run a full scan and let it remove anything it finds.
As that tool is designed to be used as a supplement to your antivirus software, I would keep it around for future use and keep it updated, just in case.