I recently went on holidays and let my younger siblings use my PC while i was away...

Now i've come back and its doing somethin very annoying, when i start it up, it goes through the POST screen and then says "disk read error press ctrl+alt+del to restart" and does that over and over again unless i leave it off for a while and try again. then when it DOES boot up, it works for a while, then restarts itself and does the same thing.

Is my hard drive dying? Or could it be something else? It's about 4 years old and has been used a fair bit.

cheers

Try changing the hard drive if possible, but my guess would be yes it's a hard drive failure.

A more simple check being to find a bootable CD and see if you can boot to that and read the hard drive.

If it was only Disk Read Error then it may have been that the bootsector had become corrupt, however if it gets past it some of the time then it indicates a mechanical fault - it can read some data before dying.

I spoke to my grandfather and he says hes worked on a computer that was having a similar problem and it ended up being his power supply intermittantly cutting out??

is that possible? I dunno whether to replace the hard drive or not now lol

take it to your local computer shop and see if they can figure out what wrong with it...

so they can charge me 100 bucks to tell me that its broken? hahahah

ok, I put my windows vista DVD into the PC to run a "repair your computer" thing.

halfway through it froze up (has now been sitting there for about 5 minutes, cant move the mouse or anything. does this tell anybody anything at all??

All hard drive manufacturers offer drive diagnostics utilities.  Download and run one for your drive.

I think it's very likely to be a failing drive, but for what it's worth, when I had this problem with my Linux machine, it turned out to be bad onboard IDE controller.  It was easy to tell because that computer had 3 hard drives and was intermittently losing not one but both drives on the same IDE interface.  I fixed it by switching all the drives to a Promise controller card I had laying around.

I downloaded a diagnostic tool, it says that the drive is running at just under 50 degrees celcius, I'm not sure what the recommended running temperature is... is that too hot?

No, that's about normal