First off, stop using AVG. It's like the ZoneAlarm of antivirus suites. Use NOD32 instead.
If the file still appears to have some sort of virus, upload it to VirusTotal where the file will be scanned by 35 different products.
Now take a look at the results. If you see a lot of virus descriptions containing "Generic/Packed/Suspicious" and the count is below 50% positive, you can probably assume it's NOT a virus and safe to run. If the all the various products tend to agree on a similar non-generic virus name, it's probably a virus.
Either way, NOD32 should prevent you from running any infected files.
As a closing note: most major scene cracks/keygens use some sort of executable packer/registry editor which sets off false positives in crappy antivirus programs. If it's really a scene release (has nfo, known group), chances are it won't have a virus/trojan.