|"what could be the problem?"|
Please post the make/model of your motherboard. My guess is the heatsink was installed incorrectly (not locked down securely or improper thermal paste application). Another possibility is the new CPU isn't supported, or it may be supported but BIOS must 1st be updated.
We need the board info.
I hope you didn't pay much for the new CPU. If you have a decent board, the 4600+ probably could have been overclocked to 2.8GHz.
message edited by riider