Seems that I said too much, too early

Well problems WERE gone, till I sold my memory at last...
Since mem prices are flying high, I couldn't buy 2 good modules here in Brazil(much higher price), and got a friend's samsung 512mb DDR400. He was using 2 of these in a system equal to mine in almost everything, just one difference, I have one more HD that's plugged into SATA with serillel.
I then put it in 400mhz and had happiness for 2 days. Then, the same BSOD returned from the dead!!! I didnt make a single change in the system in these 2 days. Now it freezes a lot.
Tried going for 333, no luck, just as bad. Well, in my case, it's not memory, because this module was working in my friend's pc. The disk warnings in event viewer had reappeared, and although they happen in the pagefile located in my PATA drive, I updated all my PATA and SATA drivers. No luck AGAIN. Since I read a lot about SATA RAID problems, I decided to put the HD in PATA and disable SATA.
Now I'm happy for about 1 hour. Let's see what happens
You would do good to disable SATA too, if you can... seems there are bugs in bioses 20+ with it and lots of others in previous versions.