to be honest, get a new CD drive. if its an IDE job, they're only, what pocket change these days?
if its not the CD drive, and the machine is an A4000 desktop, bear in mind that the IDE connector is on a part of the mainboard that is relatively unsopported. meaning that after a lot of wear, you may bend the mainboard to a point where a trace to the IDE socket breaks microscopicly, and only with a bit of heat does the metal expand and make a good connection. could also be the case for a dry solder joint on the underside of the IDE socket.
had this issue with my ol' A4000/030 and analogic out of the kindness of their own hearts charged me 80 quid for the mainboard fix, (and 120 quid for a new A4000 keyboard!)
anyway, first suggestion is get a new IDE drive, preferably a 32 speed. so you don't have to wait 10 seconds for a 52 speed to spin up or put up with it sounding like a jet plane taking off. :-)