Hatim,
From the directory information I believe the two infected files were part of the compressed files used for System Restore in Win XP or XP Pro. Some of the newer malware is cleverly hiding there because many antivirus programs have trouble picking them up in those compressed files. If your restores are infected, deletion is the best because you would not want to restore an infected file to you PC. I have seen infections there and deletions never harmed.
I also believe that any reports of crashes at installation come from trying to run two virus scanners resident, Norton resident is a particular problem as others have said. Avast installation warns you 3 times if it finds another antivirus program resident, but I've seen people ignore the warning and try to install. The result is a hard crash. To come out of it, you need to reboot into safe mode, then from control panel, add-remove programs, remove Avast. Then you can try to remove the other antivirus program, but you may have to reboot into the normal Win 32 mode and remove, or at minimum disable Norton or whatever else is running. Then you can reinstall Avast and all will be well. It is great that Avast gives three warnings that bad things will happen if you install while another antivirus program is resident, but it might be better if it just flat out refused to install.
On your original question, Avast is the best, least intrusive antivirus program I have seen. I had a subscription to Norton and was going to look at Avast when the subscription expired. But I was planning a trip to install a computer in the home of a retired gentleman in another state. I wanted to become familiar with Avast on my PC before I loaded it on his. I temporarily disabled Norton and put on Avast. It was so far superior to Norton, IMO, that I never went back to NAV. You should have no troubles, and if you do, this forum is the best tech support around. I am trying to gently persuade the college where I teach to buy Avast Pro and drop Norton as the network antivirus software.
