If you have a file that you think is sus and you want it to be scanned with an online virus scanner, I highly recommend http://virscan.org. It scans the file with all the major compedators in the antivirus industry. You can upload files up to 20MB in size.
This site also keeps a file of all the MD5 and SHA1 hashes of previously scanned files that people have uploaded. If it was previously seen as clean, it will give you the date it was last scanned and will give you the option if you do want to rescan (virus definitions may have updated quite a bit since then). This make the site fast and efficient to use.