Error messages in XP

I have a customers computer with an Intermittent well at least I did have it and it worked perfectly for me for 5 days without so much as a hiccup but within 24 hours of being returned it shut down and presented this error message

NTFS.sys
PAGE_FAULT_IN_NONPAGED AREA.
0x00000050 (0xA06113F3, 0x000000, 0xF83B2130, 0x00000000)
NTFS.sys address F83B2130 base at F838B000
Date stamp 41107eea.

The unit is built on an ASUS A7S333 M’Board had a 2100 AMD CPU 1 X 512 MEG of SDRAM unbranded a Nvidia Geforce MX440 Chip set Video Card, two Netcom LAN Cards and the SCSI card for an external scanner.

I’ve set the Page Size to 756 Min and 1,250 Max

Any Ideas?