Problem Solved!

[Mozz]

Just recently (in the last few days) I noticed that any intensive software would run fine for 5 mins and then suddenly, I would get approx 1fps for about 5 mins, then it would run fine, then 1fps for 5 mins again, with this process repeating. This made all my games (cs:source, Half-life2, Doom3) and simulators (MSFS 2004, x-plane) unplayable  :'( . Being the one taking DT for my GCSE's (I love that subject) I just opened up my PC and ran it.

Amazingly, the PC had been running with the CPU fan AND my graphics card fan not working. I've lubricated them (good ol WD40) and I've got them goin again but I'm going to buy some replacements (a whole new graphics card  ::)) Just thought I'd post this, looks like I might not be entering the screenshot comp as I said I would. Whats the likelihood of that though, 2 fans going  ???  :'(.

Oh well, Should be back up and running soon though
(the glass is half full, the glass is half full, the glass is....)
bye guys.

[the_autopilot]

I'm surprised your computer even turned on, especially if you have an Intel prescott.

[Mozz]

Thats what I was suprised at, I could even play games for 5 mins before it would start to break down, glad I found what it was before it was too late though  ;D

[congo]

Was the ambient air temperature low?

I mean, it should have fried.  

[Mozz]

Well it was winter, I guess the air temperature was low. But other than that, it must have got pretty hot but as soon as a realised I switched the pc off and got the old fans working. Got some new fans now and its stable at 40 - 50 degrees C. Must have been close though.