Thanks for your fast replies, guys =).
Well, to tell you the truth, this is a brand new system, and nothing had been installed recently in the system that could have caused such errors. If I had known about these forums back when I formatted the HD, I would have given you the dumps, but as I totally screwed up the SATA controller drivers (which I thought were the ones causing the problem), I just formatted. Later on, I started to believe it was a hardware error, since I had the same BSOD while installing XP again. I turned off the system for a couple of hours, and I tried to install XP again, but this time, I rised a bit the DDR memory voltage setting in the BIOS. The system seemed to work fine after that, but I have not installed Avast! again since then.
The problems described here previously about BSODs related with Avast! seem to be the same I had. In fact, one of the errors was about a serious NTFS driver problem (ntfs.sys). That also means it could be the harddrive, but there hadn't been any corruption issues in the previous installation, so I discarded that option. So I ran several Sandra tests and tried to run memtest86 after reinstalling WXP (this time successfuly and without any errors so far). I don't think any drivers in my system are causing this, I have SP2 and all my drivers are WHQL certified. My system is NOT overclocked at all and it's running very conservative settings.
So far so good, the only thing I have not installed yet is Avast! and everything seems to be fine. I'll do some more burn-up tests on this machine to see if there are any instability problems.
It should be noted Avast! was the last thing I had installed in my previous WinXP installation (which was fresh) before the errors started showing up, and that it was 4.5 Home Edition (the one available in download.com) and not 4.6, which appears to be the current one. Another thing I noticed is that the BSOD happened when the system accesed a big file (760MB). In fact, the BSOD happened a couple of seconds after that, about 10 to 20 sec. later. It also happened if I tried to manually scan the file using Avast! (doing right click on it, and then selecting the Scan option). In that case the BSOD also ocurred 20 sec. after that.
I'll post back with more information about this as soon as I finish testing my system.
[EDIT] My guess is that Avast! 4.5 triggered the same errors that other people were discussing, but here in my system. Those errors might be linked directly to the memory (as a Page Fault in Non Paged Area is usually caused by a driver that doesn't have enough physical memory, right?). Ramping up the voltage on the memory modules may have given my system a bit more of stability, but I'm still testing it. If everything goes well I'll set up a restore point and install Avast! 4.6.
AV apps tend to stress the filesystem, the harddisk controllers and the memory, so that may have triggered the BSOD. I'll post back with more results.
Oh, and BTW, I'm using Windows' Firewall, I don't have any heating problems in the system, and I had disabled the Network Shield from Avast!. =)
One last possibility (though highly unlikely) is that the AV was sort of "overloading" the NTFS subsystem when accessing so many files...then, while trying to access one BIG file, it took the system down...(perhaps by making the NTFS driver run out of memory?)
