what would cause this problem - weird patterns and freezing

[stushine]

my PC has recently started playing up a lot!

its about 3 years old now, spec as follows

500watt PSU
Lanparty motherboard
1 gig crucial balistix ram - was 2 gig but they kept going faulty, i give up sending them back for a replacment in the end
AMD opteron 146 cpu
Geforce 7500GT graphics card
water cooled in an akasa eclipse case

its done me good over the last 3 years but as of this last month or so its really messed up, its going really slow, takes forever to boot up, programs generally taking a lot longer to open up than they used to etc.

yesterday i put a game on, dosent require much really (ship sim 2008)
it seemed ok for a few min, then i notices little dot appearing here and there and it started to glitch a little bit, then it got worse to the stage it actually crashed and froze up etc.

ive virus checked PC
ive used a search for spyware, that found a few registery files messed up but corrected them. but still the same problem..

this is what happenes, i managed to print screen them

im planning on putting together a new build soon, but i was wanting this one to hold out for a month or 2 yet

any ideas??

 

[Fisk]

If nothing has changed (eg overclocking, fan stopped working, other sources of heat), that looks very much like a graphics card on the way out.

After 3 years, everything running slow probably means your pc could do with a good format. Though I suppose it's possible you have a virus as well, it's hard to tell without seeing it for myself.

 

[stushine]

would that cause the full PC to slow down etc?

 

[ACESHIGH]

I tend to agree looks like the graphics card is borked.