If i'll buy new CPU: Intel Pentium Dual Core E6500, will i NEED to apply Termal Grease (CPU paste)? Will my CPU work without it? I will not over-clock.
haha, no, with or without ocing it, you will fry it. Thermal paste is what allows the cpu to be in contact with the heatsink. Without it there is no heat transfering from cpu to heatsink, which means a hot cpu!
An OEM CPU is just the CPU chip itself with no heatsink and fan included. You will have to provide your own heatsink and fan and your own thermal interface material.
If it's a retail boxed CPU it will include a heatsink with fan that will have a square/rectangle of thermal interface material already applied.
Make sure you remove all of the old thermal interface material from the heatsink before you apply any new thermal interface material. Follow the thermal interface material manufacturer's application instructions to ensure you get the most effective thermal contact.