Virus Total is a free service that gives you aggregate results from 36 different malware scanners. Just browse to the file you want to check on your PC and click ‘Send file’. It will quickly return the results of all the scans, hash sizes and a list of Windows system calls that the software makes.

This is a great resource for checking software you are about to install doesn’t contain malware. It is also useful for checking that your own download files haven’t been tampered with and don’t trigger false positives. Note that some software protection systems have been known to trigger false positives from malware scanners.

Thanks to a poster on this BOS thread for bringing it to my attention.