Had Avast for years, now having problems with spyware and pop-ups. Pls help!

I have been a happy avast user for years now. I don’t know what happened last week, as I wasn’t on line for a few days, but it seems the timing may correlate with the latest Avast update. I started getting Avast notices that it blocked access to malicious content from softinvader.com. In conjunction with these alerts, I started getting a lot of pop ups. I came onto the forum and found recommendations for SUPER Anti Spyware. (Previously I had been using Spybot.) I ran SuperAntiSpyware, it found 316 infected files, which I removed. I have also been getting avast notices that a virus was found, recommends “moving to chest”, however, when I select “move to chest”, it says that it can’t, I’m sorry but I don’t remember for sure what reason it gives.
I don’t know what to do. Can anyone please advise? I’ve had avast running for years, why am I having multiple problems in the last week?

Also, running with Windows XP.

The Network Shield now has a malicious site blocking function though why that one is there I don’t know.

I would bet that a very high number of these so called infected files are cookies, a pain in the rear but no security issue, don’t accept third party cookies in your browser and periodically clear out your cookies.

A few examples of common detections, file name, location and malware name would be helpful otherwise it is all speculation on our part as to what this may be.

Commonly files can’t be moved to the chest because they are in use (schedule a boot-time scan to combat that), but you don’t say what this was.
If you have XP, vista32bit or Win2k, you could enable a boot time scan. Right click the avast icon, select Start avast! Antivirus, a memory scan will take place followed by the opening of the Simple User Interface, Menu, ‘Schedule boot-time scan…’ Or see http://www.digitalred.com/avast-boot-time.php.

What is your firewall ?

I would also suggest a visit to this site, which scans your system for out of date programs that have patches to close vulnerabilities, http://secunia.com/software_inspector/. Out of date software could give rise to the increase in detections.

Hmmm…
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 SUPERantispyware, MBAM 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 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. Disable System Restore and then reenable it again.
  7. Immunize your system with SpywareBlaster.
  8. Check if you have insecure applications with Secunia Software Inspector.