CPU need for micro BTX motherboard new build

Hello everyone.
I have a Gateway GT5235E media center that has not worked for some time due to the onboard video chip went out. And a card will not work. So I decided to replace the motherboard, that is when I made the mistake in getting the wrong size. But did find a Intel D945PAW-PB micro BTX from factory board that fits. Now I have a problem I don't understand what I should be looking for in a processor/cpu . I don't know if I am to look for the chipset that is 945P or the socket that is LAG 775. I have found that this motherboard can take the following compatible processors, Intel Pentium 4, Intel Celeron D, and Intel Pentium D.
This motherboard has the following.
Front bus speed 1066 MHz.
Video Interface PCI Express x 16
Storage control types DMA/ATA-100.
Fire wire 1 IEEE 1394 X 1
South Bridge chip ICH7R.
Max support cpu 1
Memory type DDR2 SDRAM
Number of slots 4 X 240 Pin DIMMs
Support Ram Speed 533MHz-400MHz-667MHZ.
Bios Features Plug an Play-smBios 2.3-ACPI.
This computer will only be used for everyday task not one for playing games.
I have asked this question on other forums and because of the microBTX motherboard I have not got any answers

 

Thanks PeteC for getting back so quickly. Now I can get this computer running. I see that they charge different prices in different location for the motherboard I have, I payed only 16.95 for but not sure if I am allowed to give the name of the place here.