I bought a PDQ on ebay for $5 plus shipping.

It works fine except for one thing. After a short time of use, the internal drive will startup and do a self-check, and then power down. It will repeat this issue and it will not boot from CD while it does this. Last time it just eventually turned itself off.

I have changed the hard drive cage just in case the circuitry on it were at fault but it did not change anything. Does anyone have any ideas on what would cause this? I have reset the pram but it didn't do anything other than run the fan at full speed.

Thoughts?