I was right, it was the heatsink. A £10 heatsink later and my computer seems to be working perfectly AT LAST.
As for the crazy eyeballness a few days back? I saw an optician about it, and apparently I had an "ocular migrane". Apparently nothing to worry about, and that normally sends people into a panic the first time around unless they've heard of it (in which case it just makes them uneasy), but a condition that isnt really common knowledge. So, for those who shiv a git, rather than me trying to recite what I was told, and for those who are too lazy to (or too distrustful of) wiki, feel free to read up here :
http://www.eye-surgeons.net/migraines.htm So, my computer now works after three weeks.
My eye ISNT transmitting illuminati secrets through stroke-inducing blobule-lights.
I just stumbled on some chilled mp3s I ripped from that old Lucasart game "Afterlife".
I have plenty of pepsi max.
And still no zombie infestation.
Good times.