I have an Intel 945GNT Motherboard along with a Pentium D processor running at 3.4GHz and 3 sticks of 1GB RAM at 533MHz. I have given it to one of my engineers for repairs and he said that the motherboard is dead as one of the components got overheated although the processor seems to be fine. I would like to know where if possible i can get another D945GNT motherboard OR what motherboard would be good replacement for the D945GNT so that i can continue to use the same processor & RAM sticks?

This = NO

The Foxconn P4M800P7MB-RS2H motherboard supports ram memory that is either 400MegaHertz, or 533MHz.

You have installed 667MHz ram memory.

http://www.play.com/PC/PCs/4-/3274794/-/Product.html

You also need to watch the Front Side Bus (FSB) of the processor you are using.

Ram memory typically operates at HALF of the FSB of the Processor.

Processor FSB support is 800MHz maximum.
Half of that is 400MHz.
You CAN use 533MHz ram memory, however.

(This is DDR2 Sdram ram memory.
PC2-3200 is DDR2 at 400MHz.
PC2-4200 is DDR2 at 533MHz. (Also known as PC2-4300. Depends on the ram memory manufacturer.

PC2-3200 actually operates at 200MHz. { Max} It is 'Dual Pumped'
PC2-4200 actually operates at 266MHz )

What to do?
Hopefully you saved the carton/s the ram memory came in.
Ship them back, get the ram memory you need.

ALSO;

What is the FSB of the Processor you have installed?
Don't know?
Post back in a Comment as to the model name, and model number.

(Example; Intel Pentium D model 805,

http://en.wikipedia.org/wiki/List_of_Intel_Pentium_D_microprocessors#.22Smithfield.22_.2890_nm.29

FSB support is 533MHz
No, you cannot use 533MHz ram memory. { PC2-4200 }
PC2-3200 is the max.

Pentium D model 820 for example, you can )

Hardware Support
The Biostar i945GZ 775 SE supports RAM a maximum of 2GB using its two 240-pin DIMM slots, each can be populated by a 1GB stick. The board supports DDR2 400 or 533. With two identical RAM sticks installed, the board will switch in dual-channel mode operation.For the support of processor, the board can accommodate Intel Pentium 4, Core2Duo and Pentium D, even Celeron D, all with clock speed up to 3.8GHz; and all are based on a LGA775-pin socket architecture. use an Intel Pentium D 820 2.8GHz (dual-core, Smithfield) processor on this board. use the following components to complete the system: CPU: Intel Pentium D 820 (Smithfield) 2.8GHz, dual-core
RAM: Hynix PC2-3200 2x512MB (1024MB) DDR2 400 HD: Seagate SATA-I Barracuda 7200.8 250GB CD/DVD-ROM Drives: HP dvd640, Phillips DVD-ROM

Depends on the socket type.. Socket 423 and 478 do not support core duo or quad core processor types. However, if you have LGA 775 (aka socket T) your motherboard will support the following:
Intel Pentium 4 (2.60 - 3.80 GHz)
Intel Celeron D (2.53 - 3.60 GHz )
Intel Pentium 4 Extreme Edition (3.20 - 3.73 GHz)
Intel Pentium D (2.66 - 3.60 GHz)
Pentium Extreme Edition (3.20 - 3.73 GHz)
Pentium Dual-Core (1.40 - 3.33 GHz)
Intel Core 2 Duo (1.60 - 3.33 GHz)
Intel Core 2 Extreme (2.66 - 3.20 GHz)
Intel Core 2 Quad (2.33 - 3.00 GHz)
Intel Xeon (1.86-3.40 GHz)
Intel Celeron (1.60 - 2.40 GHz)

If you are using Dual Core the mother board you are using may have PCI Express Slot. So that you may install Graphics card. Only for particular lower end mother board doesn't have this feature. Any way tell me your motherboard make and model no. e.g., Intel DG31PR, 945GNT, DG41TY etc.,

The intel 810 motherboard will not support DDR2 memory.
Intel Pentium 3 Socket 370 SDRam PC100 Ultra DMA100 Motherboard With Onboard Video / Sound & LAN! For Intel Pentium 3 Processors (CPU.
This board will only support SDRAM PC100

IT supports Maximum 2GB DDR400 RAM.
It mainly depends on the Processor speed.I think 1gb RAM is sufficient for Your Pentium 4 configuration. If you use more than 1Gb.there is no remarkable speed difference between them.So better choice is use 1GB RAM.

That additional RMA will be good for your computer so it will be much faster and don't worry everything should work fine there after adding new RAM to your computer....

You'll be fine. If you have been on crucial you know then whether the modules need to be in matched pairs, which is what it looks like you are doing. The only limitations on RAM are when you go to 4GB using 32-bit processing. It will most likely not all show. But with 2.5GB, you should be humming along quite nicely.

That additional RAM will be good for your computer so it will be much faster and don't worry everything should work fine there after adding new RAM to your computer....

This may sound counterintuitive but its just a suggestion. I see by your prior post you are using a PC2-4200 1GB ram stick. Have you tried using faster ram? I suspect a FSB timing issue, even though by the numbers it should be running at 533MHz (which is 5x133).

This motherboard defaults to setting the clock speed by SPD (serial presence detect) but can be set manually in the BIOS. See if you can beg/borrow a PC2-5400 stick to see how it affects the timing and performance.