Avast freezes during scan

[Dumpy Dumpster]

Just installed Avast and tried my first scan.  But the scan froze several times and always at the start of C:\System Volume Information.  I have removed the Tracking Log file from System Volume Information whilst in Safe Mode as that used to cause AVG to freeze also.  I also seem unable to run Avast in safe mode.  So questions are:
How to work around freezing problem?
How to operate Avast scanner in Safe Mode?
PC details are: Dell 5100, Win XP SP2, Avast v. 4.8.1169, VPS v. 0805 18-0, Pentium 4 800 MHz, 512 RAM, ADSL connection, no messages appear at the freeze point.

[Lisandro]

Are you referring to AVG antivirus? Are you using two antivirus at at the same time?
Also, you can try to update avast to 4.8.1201.
If you disable system restore (deleting old restore points) and enable it again, could help...

[igor]

Btw, the tracking.log file is related to ZoneAlarm, so that's probably the real guilty one (of the freezes) here.

[Dumpy Dumpster]

Thanks igor and Tech for your replies.
I have now used the boot scan which was able to complete without freezing ( and found no viruses)
I had actually deleted the Track Log file immediately before scanning as that worked with AVG (anti-virus) but not the same result with Avast.
I only use one anti-virus programme - the AVG  I referred to was AVG Anti-virus.
Thanks again, I will perhaps just stick with boot scans in the future