My computer has been acting weird lately, it boots normally only when I shut it down, if I restart, it boots in half an hour. and the startup process: "Press any key to boot from CD or DVD....." which normally takes a few seconds now takes a minute. The computer boots as if in slow motion. I recently replaced my heat sink, and some thermal paste got on the parts of the CPU which the thermal paste aren't supposed to reach, does that have anything to do with it?
Have you replaced anything else? (anything that would cause software glitches?) You haven't made any changes in BIOS, etc? (I'm just asking because most people get a new heatsink to overclock...) It seem to me that this is more likely to be a software issue. Hardware tends to either work or not work -- less of this in-between stuff.
Post full system specs too. including age of system.
id you use a silver based thermal paste like AS5? If you id you could be in trouble as it conducts electricity. Also might want to make sure it was mounted correctly when putting it back, also check your HD. Your drive may be dying.