Internet Problem please help me.?

Typically if the CPU overheats, it will shutdown the PC and upon re-boot you will see the bios message the the CPU has/had overheated. Never heard of a CPU kicking you off the Net, sounds more like your NIC than anything...but if your MOBO is getting hot as a result of the CPU, then that could cause MOBO bus to disconnect from the hardware, but I have never seen anything like that - look towards NIC..Also some MOBO's Bios let you watch the temps - turn on your system get in to your bios and check them out for about 1/2 hr or so...even with Overclocking you should never get above 85 C