Avast not detecting trojan win32.generic!BT

Viruses and worms
1

I have avast pro, which updates regularly, and also malwarebytes which I run weekly ( daily when running slow ). A few days ago my lappy started to run very slowly so I ran scans etc as usual but nothing was detected. Yesterday I downloaded and ran ad-aware which detected the trojan ( win32.generic!BT ). I quarantined it and things were much better. Today was slow so ran ad=aware again and up popped the same trojan! The quarantine chest says there are 2 of the same trojan in there. Why would avast miss them? And malwarebytes too? Both are updated regularly and both missed these bugs.

I am confused, 2 trojans or the same one ( incidentally #1 detected on smart scan, #2 on full scan ). How many programmes are needed to keep a computer free of viruses etc?

Any advice would be very welcome.

2

What if the detections from Ad-Aware is False Positives ???

upload the files to www.virustotal.com and test them with 43 malware scanners. When you have the result, copy the URL in the address bar and post it here

3

I suggest:

  1. Clean your temporary files.
  2. Schedule a boot time scanning with avast with archive scanning turned on. If avast does not detect it, you can try DrWeb CureIT! instead.
  3. Use MBAM (or SUPERantispyware or even Spyware Terminator) to scan for spywares and trojans. If any infection is detected, it is better and safer to send the infected file(s) to quarantine (Chest), rather than simply deleting them.
  4. Test your machine with anti-rootkit applications. I suggest avast! antirootkit or Trend Micro RootkitBuster.
  5. Make a HijackThis log to post here or this analysis site. Or even submit the RunScanner log to to on-line analysis.
  6. Clean your Hosts file (replacing it) with HostsMan tool.
  7. Disable System Restore and then reenable it again.
  8. Immunize your system with SpywareBlaster.
  9. Check if you have insecure applications with Secunia Software Inspector.