I can't get the old compound off of the heatsink. I tried using isoprophyl alcohol to remove it but it won't come off.

I'm guessing this is the heatsink that came with the processor and this gunk is what's left of the pad that is used in between the two.

Try using lacquer thinner.

If it's dried paste you an use lighter fluid or thinner as OtheHill mentions. I've also used something called Oops! from Walmart.

If it's glue you may need a razor blade to scrape it off.

It sounds like it might be glue -some people actually do glue the heatsink to the CPU. Isopropyl alcohol usually does the job pretty well.

If you do have to use a razor blade be very careful you do not scratch the heat-sink. Scratches can effect the thermal transfer qualities of the heat-sink.

Best thing is to remove the bulk of whatever it is with a razor blade them remove the rest will a mild abrasive like Brasso. It is laborious but gets the job done.

Stuart

It seems to be off-white, maybe kind of pinkish in color, it's really sticky and seems to only kind of spread around when I try to scrape it off.

Thanks for the suggestions but does this apply to the CPU also, since this stuff is on the core also.

Thanks

Sounds like thermal paste. Clean with lacquer thinner.