Debian Sarge: Intermittent random crashes

Hi all

My PC running Debian Sarge gets crashed intermittently without any (apparent) relation with any specific operation: during the initial installation process, during booting, during X Window loading, during log-in, during a calm GUI session (GNOME or KDE behave the same).

So: it's totally unpredictable!

It's strange that I've been operating this same machine for over a year using Windows XP and it NEVER crashed frozen...

I've now added Debian Sarge on a separate hd (see below), and the two systems behave in opposite manners (Windoz keeps working, Debian keeps crashing...).

I've already tested ram through memtest86+, but no error was reported after an 8-pass execution of all the 12 tests.

My BIOS settings are much conservative (no overclocking, no hyperthreading etc.).

I feel really stranded...

My configuration:
CPU: Intel Pentium 4 3GHz;
Motherboard: ASUS P4P800-X;
Primary IDE master (Debian Sarge partitions): Maxtor 6B160P0 (P-ATA 160GB);
Primary IDE slave: (void);
Secondary IDE master: LG CD-ROM CRD;
Secondary IDE slave: Western Digital DVD-RW SOHW;
3rd IDE master (Windows XP partitions): Western Digital WD1200JD (S-ATA 120GB);
4th IDE master: (void).
.