OK check this out.
Got the CD drives working but now what started happening is my computer would WORK fine for a while then it would start freezing up for about 30 seconds every COUPLE of minutes. I noticed that when it started freezing, the cd drive would then stop working again - light would come on, door not open, not recognized. Being the superstitious TYPE, I thought they might be related so I DISCONNECTED the cable to the CD drives, and lo and behold, my computer stopped freezing up. It looks like something having to do with the drives was causing the freezing?Were the drives being accessed when the "freezing" occurred?No.OK so its got to be related to your CD drives so,

Buy a new one , and get a new Ribbon cable as well

I'm sure if your nice to the store Clerc you can buy a CD-RW drive for like 30Quid and get him to give you a ribbon cable for freeWell no amount of replacement parts (apart from a new motherboard) is going to fix this if the onboard IO controller has died.

"Oil"? Any kind of conductive liquid inside a PC can cause all sorts of damage and bizarre behaviour.

Before you buy any new gear, it would be best to borrow known working equipment for testing purposes - the CD drive and cables as suggested above, being the FIRST place to start. Don't worry - your computer's malaise is highly unlikely to spread to the borrowed equipment.

Unless that liquid is, say, hydrochloric acid...