Fuzzy screen image freeze and crash

Ten minutes after logging in the screen turned fuzzy and the game froze. I was unable to get to the taskmanager and had to close down the PC. When I tried logging in again the same happened at character selection.
I have benn playing GW on this machine for roughly 7-8 months (that is how old the machine is)
I have all campaigns and EotN, this happened in NF. The only other game I have installed - Oblivion, runs fine; I tried it afterwards.
The disk gets defragmented regularly, I use AVG antivirus and spyware as well as Ad-aware. The drivers are up to date.
System:
Fujitsu-Siemens Intel Duo T7200 2 GHz (Notebook)
1 GB RAM
ATI Mobility Radeon X 1800
Windows XP

Does anyone have any suggestions as to what I could do?
I saw someone mention getting GW to use only one core, but as it has worked as is up to now I would prefer not to fiddle with that if possible.
Ideas please?

Sounds like GW.dat may have got corrupted. Tried redownloading?

I haven't tried that, mainly because I am on dial-up from South Africa and it will take literally days...
Oh, well, I will save the current one elsewhere and do it. Should I do a complete re-installation as well?

Just had a thought. Could I use the DAT. file of someone else? I recently introduced a friend to GW; I gave him my DAT. file some two weeks ago.

Would hurt,the other files are small.

I hope you meant "wouldn't"...
Do I have to use all the CD's again if I do a comlete reinstallation? Sorry, I just don't want to bollix myself even further.

haha! Yeah, wouldn't. Sometimes I type too fast.

All you need to do is delete the .dat file, the GW.exe will automatically start to redownload the .dat file fresh when you next try to start up