Just installed Avast 4.8 free edition and did a thorough scan. When scan finished, laptop turned off. When I re-started, laptop did a disk check. Scanned again and same thing happened. Is this normal for this to happen with this version or do I have something set wrong? ???
System: Acer 2450 Laptop
Windows XP - Home Edition - SP3
Explorer 7
Windows Defender
SUPERAnti-Spyware
Ad-Aware
Avast 4.8
Thanks for any info !
This is not normal.
If computer reboots during the boot time scanning (or turn off), there should be a hardware problem, or deactivated fans and overheating…
Are there more info in the report? Avast4\DATA\report\aswBoot.txt
Did a Boot Time Scan, which went OK. Then did a “Standard Scan”, which also went OK. Tried a “Thorough Scan” next; laptop turned off again. Checked and cleaned fan, checked core temperature…HOT !! :o
Looks like I have to stay with doing standard scans and/or get a laptop cooler I guess.
Thanks for the help! 
How much dust and stuff was around the CPU and fan?
If it was significant, you may have fixed it. Also check that where the laptop is sitting when you are scanning provides an unnimpeded airflow.
Well a Standard scan without archives is fine.
Archive (zip, rar, etc.) files are by their nature are inert, you need to extract the files and then you have to run them to be a threat. Long before that happens avast’s Standard Shield should have scanned them and before an executable is run that is scanned. Thorough is also by its design very thorough and perhaps a little overkill for routine use, were a Standard scan without archives should be adequate.
I have only ever done a Through Scan with Archives once shortly after installation just to ensure a clean start state, but with XP for example avast will do a boot-time scan after installation if you select it, this I believe will be quicker and reasonably effective. Like everything in life things are a compromise.