Upgrading CPU on 775 socket

Hi all,

I bought the MSI p35 platinum motherboard about 2 1/2 years ago because I thought I'd upgrade to a 45nm CPU later on.

I recently bought a Pentium dual-core E6500 to swap with my old E2140.
After I installed, it would not boot correctly. Looking at the LED status indicator on the motherboard, it shows that "Testing Base and Extended Memory, Testing base memory from 240K to 640K and extended memory above 1MB using various patterns."(from the manual) It would get stuck or repeat the process when it shows this pattern of the LEDs. When it does get stuck, the screen gets stuck on the booting screen, where it asks to press del to show bios.

How can I solve this?

Thanks in advance.