How to unglue microprocessor from heat sink?
How to Remove a Processor Fused to a Heat sink:
The processor should easily come off the heat sink. If you have any problems be sure never to pry the processor off or use any metal objects (including a razor blade) to get under the processor for it will damage the heat sink and likely the processor.
First try to gently twist the processor, being careful to avoid bending the pins. Do not apply too much force.
If twisting does not work, soak the processor/heat sink in 90-95% isopropyl alcohol (this will not damage the processor) for ~5 minutes.
With a long string of dental floss gently floss the area between the processor and the heat sink, starting at any corner where the floss is able to penetrate.
As you go along the processor, go back and forth while applying force in the direction away from the corner where you started. It may be difficult at times, but it will go through.
Alternate Method - Use a 'heat gun':
Turn your heat gun to high and heat each flat side of the CPU for 10 seconds, keep the nozzle of the heat gun 2 cm away from metal surface. Be careful! Make sure that heat is not hitting the CPU itself as it may damage transistors.
Firmly hold the HEAT SINK and gently turn the CPU clockwise and counterclockwise.
If the CPU does not turn, apply more heat to the heat sink. The warmth of the heat sink will 'unglue' the transfer paste.
The reason the CPU fuses to the sink, is because the heat transfer paste is of poor quality. Once the paste reaches a certain temperature, its molecular structure is altered slightly and it acts like a glue. So if your heat sink is cold, your CPU is stuck. Just make sure you are careful not to apply heat directly to the CPU and this method should work. The isopropyl method is great, but it is to easy to damage your CPU or mainboard, if anything has any H20 (water) remaining when you plug it all back in!
Tips:
Use dental floss. It works great!
For additional help, soak the dental floss in a heat sink compound remover, commonly found for sale by online PC component vendors.
You can also use 90+% ethanol, or take a risk and use 70% isopropyl or ethanol.
If you are unable to find any isopropyl, methylated spirits works just as well.
To check if the liquid you are using is suitable, rub some on glass. If no marks are left when it dries, it is good to use.
Soak the dental floss in the 90% or + isopropyl. Make sure you have a long enough piece of dental floss to wrap around each hand 2 or 3 times and still have a foot in the middle. Work the floss in one of the corners of the processor and heat sink. Once you get the floss inside one of the corners, grip the heat sink with your feet on the floor with the processor facing up. Now, go back and forth with the dental floss, lightly but fast. Work your way to the opposite end of the corner and the processor will pop off.
Warnings:
Avoid damaging the heat sink, unless you do not intend to use it again.
Do not use acetone, as it may damage the silicon.
Things You'll Need:
90+% isopropyl, ethanol or methylated spirits
Dental floss
Source: wikiHow
Heat works well, but you don't need a heat gun. Use an electric cooking range and put the heat sink with fins down on the burner. Put the heat on high and touch the opposite end (the one stuck to the microprocessor) until temperature gets uncomfortably hot. Use a pot holder and remove from heat, hold the heat sink with the holder and twist processor with bar fingers (will not be hot). Should twist right off!