SATA discs disappear in Windows XP

[ripper079]

Athlon XP 3200+
Asus A7N8X-E Deluxe (Rev 1012)
1,5GB RAM PC3200
Seagate 200GB IDE (Windows partition)
2 X Seagate 120GB SATA (striping)
GeForce 6800 GT
CI-6A21 300W


After having tons of problem with my Windows XP installation I finally got it to work (with service pack 2). After installing appropriate drivers to all the hardware components all seemed to work fine. But after 4 days the 2 SATA discs just went down. BIOS doesn´t report any errors about the discs but when WinXP starts its not there. I´ve also downloaded some app from Seagate to fix the problem but with no luck. Norton AntiVirus hasn´t detected any form of virus. Does anybody have a clue why the discs are gone?