Motherboard change. Won't boot up

My old motherboard (MSI P4M900M@-L MSI Global ? Mainboard - P4M900M2-L) was not working as in the display was blank and no signal was being recieved by the monitor. So I went shopping and they sold me a new motherboard (MSI G31TM-P31 MSI Global ? Mainboard - G31TM-P31). After i installed the new motherboard, i turned on the system and the blue light was on and the fan was spinning. after a short while the fan started spinning much faster. So I went ahead and tested the processor on another computer and it was working properly. The processor is a Pentium Dual-Core (I will post model number if requested since it's a bit hard to take off with the fan and all).

What should i do? is it an incompatible motherboard? since the motherboard doesnt have onboard speakers, it doesnt make any sound either. Thanks in advance

CPU: Pentium Dual-Core
Conroe SLA8X E2200
FSB: 200MHz
Speed: 2.20GHz

It should be compatible with your processor. Make sure you have everything seated properly, cables plugged in properly, including both motherboard power cables, and then try resetting your CMOS.

I connected 2 cables from the power supply to the mainboard. One has 4 Pins. The other has two cables (one has 4 pins and the rest i think maybe 20) which come together to form one cable. Both are connected. Then the only connections are to the hard drive, the IDE DVD ROM, and the small connectors to the power switch and reset switch + the LED'S (All work)

I will check the motherboard connectors. And yet the HDD and DVD drives have two cables all connected. I'm trying to get it to work with onboard graphics since it's an office computer and doesn't need anything more than integrated. I do have a Nvidia 9800GT card that I could use though. I tried it but the results were the same. I will check the connectors and tell you later.

As for the beeps, i can't see any of those small speaker/beep things on the motherboard so i assume it wont make a sound either way. Also the fan connector is properly connected and so is the RAM in the first (DIMM1) slot.

Okay, so I checked all the cables and reseated them all properly and they fit in just perfectly. But There is still no signal to the monitor. One thing i noticed was when i connected the HDD and booted it up, the light on the motherboard blinked once

Okay, more info; The fan speed up after a while of keeping it on. Also, i noticed that the HDD does start spinning but i cant hear anything moving inside (the read head)

Also, There seems to be no power to external devices like Keyboard or USB pen drives. Perhaps it's a faulty PSU?

Disconnect your hard drive and optical drive until you can get it to post. Also unplug anything you don't absolutely need for the PC to post, like USB printers, external drives etc. I might even disconnect the front panel audio cable, USB header cables, and leave only the case power button connected. In rare cases I've seen a PC not post if the power LED or hard drive activity LED was connected back wards. Start with the bare minimum, power supply, motherboard, CPU with heat sink, one stick of RAM. Once you can get it to post into the BIOS, then start plugging things back in one at a time.