Swapped CPU now no signal or boot

Hello. I know there's lots of these posts but my problem is different.

I have a 766id eMachines that has a 766 Intel processor. I switched this processor with a 1.3GHz Intel processor from another eMachines of the same socket type. After switching and plugging in the fan on the heatsink, the computer boots with HDD activity light constantly on, the CD activity light blinking and no beeps or video output. So, I switched the CPU back to the original, but it gives me the same problem with original hardware. I cleared the CMOS with the jumper... that didn't do anything so I removed the battery, also to no avail. Does anyone know if I fried the mobo? I contacted eMachines and they said something about Windows XP (Pro is what I'm running) saves last config, but I don't see how that would affect boot. Any help is appreciated!

there are more than one type of pentium3 processor, even if they are the same socket, for example soket 370, 370 pin PPGA, 370 pin PPGA FC-PGA1, ....there are a few more i dont remember the letters for off hand, anyways your motherboard has to support not only the processor but the speed as well, if your board only supports, for example 500mhz to 1000mhz, this could be the reason, sometimes a bios update adds more processor support but if this is a Tualatin p3 and the board is for the older flip chip, it wont work. i have seen adapters listed in several catalogs, but if they work or not is beyond me.

Was there any activity on the mainboard it self? ur processor fan might have failed (which in turn could lead to your processor bieng burned out)