Computer issues - tech genius required :(

Since this has been going on for a year and nobody in the world seems to have a clue why, it's unlikely that I'll find answers here. However, I'm completely desperate, just about ready to cry, and if anyone does happen to be a techy sort you have no idea how much I would appreciate some input.

Apologies in advance, I don't really know the words for things so am just describing the problem as best I can.

The situation:

My PC works fine, until I try to do something really intensive like gaming. The whole machine will suddenly start to run very slow, and upon further investigation there will be an error in the event viewer thing. This error varies slightly but is usually one (or a combination of) the following:

"The driver detected a controller error on DeviceHarddisk0D."

"The device, DeviceIdeIdePort0, did not respond within the timeout period."

"An error was detected on device DeviceHarddisk0D during a paging operation."

Once this happens, the whole computer will run extremely slowly until restarted. Unfortunately, restarting it doesn't work. The first time, when starting back up, it'll stop and say "disk read error" and I have to ctrl-alt-delete to restart again. The second time it'll get further along, but just as Windows is loading it'll bluescreen and reset itself again so fast it's impossible to see what the bluescreen message is.

This cycle will repeat (disk read error, bluescreen, disk read error, bluescreen) until I turn the whole thing off, leave it for around 10mins, then turn it back on. Then it'll be back to running great until I try to play a game.

What we've tried replacing with no effect whatsoever:

• Hard drive (twice)
• Motherboard
• Processor
• Power supply
• RAM
• Graphics card

I've also tried stuff like only playing games when there's nothing else running, endless malware scans, turning all game settings down to the lowest. Waste of time.

I'm basically at the point where I'm so desperate, I'm just going to post this in every conceivable place online until someone comes up with a theory. Please, no matter how crazy it sounds, if you think you know why this might be happening feel free to share. I can't answer any particularly techy questions but I can relay them to Other Half who is much more knowledgeable on this stuff.

Thankyou thankyou thankyou, and sorry for the completely OT thread.