Hey, on an update to my problem and the final solution, what I did was disable EXTERNAL CACHE on my Asus P5A-B motherboard using the Award BIOS version 1010 Beta 2 (although it might work with previous versions). The computer stopped crashing and became completely stable, however, there is a little slowdown, but so unnoticeable that you only notice it if you know that the EXTERNAL CHACHE was disabled

I'm a bir sceptical of p5a motherboards...so many "fixes" lately (updating my riva tnt to a newer generic one, registy hacks, bios settings...).

What has worked for me is keep on using 1007.A final bios. It is kinda stable, and it works now. Anyway, I will try this fix this time. I pray for this to finally getting an stable OS like linux :-)