861003 - AMD64 & memtest86

hi
after a lot of blue screens with different texts and id's, i decided
to run memtest86 test program to see whether my computer's memory is
working fine. two 512 MB DDR 533 are located in slots of K8NF4
motherboard. i did it and the test behaved as follows:
first, a full screen of texts appeared, including gauges (text
progress bars). then, the top-half of screen got black and some texts
continued working in the other half. not as fast as it was.
periodically it outputs some changes and it seems to be stalled in
most of the time. sorry for my bad english. when i left it for some
minutes, and come again to see what was happening, i saw that the
following error (exception) had occured:
Unexpected Interrupt - Halting
i changed the bios settings to default. no overclocking. nothing above
normal, etc.
the blue screens i've encountered have been:
- PAGE_FAULT_IN_NONPAGED_AREA: 0x00000050 (x,0,x,0), nltdi.sys
- DRIVER_IRQL_NOT_LESS_OR_EQUAL: 0x000000D1 (0,2,0,x), tcpip.sys
- PFN_LIST_CORRUPT: 0x0000004E (7,934e,1,0)
- DRIVER_IRQL_NOT_LESS_OR_EQUAL: 0x0000000A (0x00000000C000021D,2,0,x)
these were encountered more than once until i uninstalled ESET NOD32
Smart Security x64.
then i installed Kaspersky Internet Security. i also changed the boot
device from slave to master. configuration now is boot HDD is master
with CD drive in slave. another HDD is on the 2nd bus.
now i get:
- SYSTEM_SERVICE_EXCEPTION: 0x0000003B (0x00000000C0000005,x,x,0)
as well as the memtest86 fail.
thank u for any assistance or giving a way to get closer to the source
of the problem.