Inspiron 1150 CPU upgrade...

Hello,


I upgraded my dell inspiron 1150 Cpu from a 2.6 celeron to a 3.2 P4 mobile cpu.
the machine booted fine and worked fine for some time.
though after a while it shut down due to a over heat and now when i boot the screen is blank,
the fan comes on , the hard drive starts and shuts down then the fan stops.
i reinstalled the 2.6 and everything is as it was before the upgrade.
i know this 3.2 should work because through research i found that others have used a 2.8 P/N SL725 with no problems
and the 3.2 P/N SL77R both have the same specs.
I am at a loss any guidance would be great.