Power off and unplug the WIDE IDE cable from failing drive. See if it does that after you boot after about the same amount of time. If you leave the case cover off, the reduced heat may fix so so be sure not to change the conditions of this test.
I'm having trouble with my Philips CD-RW.
After about 1 hour (approx) after booting up my PC, the tray starts jumping
in-&-out all by itself. Nothing I do seems to help. I even re-formmatted my HD and reloaded all my software from the original install discs.