pleeeease help me!!!

[mcf1]

Hi kaleuns.
I have a serious problem with my pc and thought, you could help a bit.
Well all games I try to play on my pc (SH3, IL2, fs9, fs 2002 etc.) they all crash after a few minutes of play time, no error reports appear the screen just blanks and the desktop appears
Everything started about a week ago and I haven't installed any new devices or drivers, I thought that windows was causing that so I reinstalled them, but the problem remains.
I installed another game and gave me this after the crash:

* * * Vampire Crash Data Log, Generated From Exe Built On: Oct 6 2004 * * *
vampire caused an Access Violation (0xc0000005)
in module engine.dll at 001b:200f5a77.
Read from location 00000000 caused an access violation.
Context:
EDI: 0x00000008 ESI: 0x1048faec EAX: 0x03799c00
EBX: 0xffffffff ECX: 0x00000000 EDX: 0x00000073
EIP: 0x200f5a77 EBP: 0x20d5e0b8 SegCs: 0x0000001b
EFlags: 0x00210206 ESP: 0x0012e6b8 SegSs: 0x00000023
Bytes at CS:EIP:
8b 11 a3 48 09 2b 21 a1 3c 09 2b 21 83 c4 14 50
-----[ SysInfo ]-----
Error occurred at 6/24/2008 08:34:26.
2 processor(s), type 586.
42% memory in use.
1280 MBytes physical memory.
731 MBytes physical memory free.
3055 MBytes paging file.
2319 MBytes paging file free.
2048 MBytes user address space.
1560 MBytes user address space free.
-----[ StackTrace ]-----
0x73656E65 : <unknown symbol> in <unknown module>
-----[ ScopeTrace ]-----
SCOPE_TRACE data, stack depth = 3
02. RunListenServer ()
01. CEngineAPI::Run ()
00. LauncherMain ()

can anybody help me here?
thanks in advance
EDIT: i forgot here are my specs

Windows xp sp2 home edition
Intel pentium 4 2.6 Ghz
Nvidia Geforce FX5200
1.25GB ram