[dba-Tech] PC problem

Hi all
 
I've got a "slight" problem with my PC... yesterday, I was playing Company
of Heroes, and just as I was about to storm the German headquarters, my
screen turned several shades of pink, with yellow lines radiating out from
my mouse cursor... this carried of for around 30 seconds, before the PC
restarted itself.
 
When it restarted, it had lots of green wavy lines on the screen (both of
them), around half an inch long, in sets of four, one pair slightly offset
above and to the right of the other. Since then, I have downloaded new
drivers for the graphics card, run 5 anti-spyware programs, 3 anti-virus
programs, Trojan Hunter, run disk clean, defrag, even done a chkdsk from the
Windows CD. After none of those worked, I did a repair install of windows.
That's not worked either, and I've spent the rest of the afternoon putting
all the windows updates back onto the PC.
 
I've even tried using the older drivers that I had installed before
downloading the new ones.
 
One thing it is doing now that it wasn't before, every time I try and resize
an internet explorer window, or even close it, is to blue screen and tell me
that there is a problem with nv4_disp.dll, so I googled it, and downloaded a
replacement one from a trustworthy looking website (www.dll-guide.com), but
it's made no difference.
 
I think I know the answer to this, but I'm hoping to try and get away with
not having to buy any new hardware... does anyone have any ideas?
 
 
Jon