Disable System Restore and reenable it after step 3.
Clean your temporary files.
Schedule a boot time scanning with avast with archive scanning turned on.
Use AVG Antispyware; SUPERantispyware and/or Spyware Terminator to scan for spywares and trojans. If any infection is detected, better and safer is send the file to Quarantine than to simple delete than.
I would suggest a scan in safe mode with SuperAntiSpyware as I’m not convinced this is blaster or lovesan. I have no doubt that they are malicious it is just the name assigned to the detection.
You could also check the offending/suspect file at: VirusTotal - Multi engine on-line virus scanner and report the findings here. I feel virustotal is the better option as it uses the windows version of avast (more packers supported) and there are currently over 30 different scanners.
Or Jotti - Multi engine on-line virus scanner if any other scanners here detect them it is less likely to be a false positive. Whichever scanner you use, you can’t do this with the file in the chest, you will need to move it out.
Note:
To Upload to VirusTotal - Multi engine on-line virus scanner and report the findings of these files here. If any are detected by multiple scanners send example to avast, see below.
Create a folder called Suspect in the C:\ drive, e.g. C:\Suspect. Now exclude that folder in the Standard Shield, Customize, Advanced, Add, type (or copy and paste) C:\Suspect* That will stop the standard shield scanning any file you put in that folder. You should now be able to export any file in the chest to this folder and upload it to VirusTotal without avast alerting.