CPU 'downgrade' - system won't boot

[issepower]

Hi,

I've installed a core i3-540 in an acer aspire x3950 (had i3-550 before) and now the system won't boot. Well, it boot's but I see nothing on the screen and I don't hear the hard drive is booting into Windows. Video output is the integrated graphics.

Any help would be appreciated.

 

[Z1NONLY]

I'm guessing there was an issue that prompted you to downgrade in the first place?

Why did you change your CPU?