Ddr3 graphics card with ddr2 motherboard

The PSU is sufficient and there is no problem in running a DDR3 GPU on a DDR2 mobo. That only matters for the type of RAM you put on there.

It will work, but why the 5450 2G ? You're not planning on gaming i assume ?

thanks for answering, but i am using 4 gb ddr2 ram in my mobo. My gpu has pci-ex 2.1 suppot,but my mobo has slower 16x pci-ex slot..will this be a problem??

I am casual gamer,thats why brought this card. But now the card is not working well. During games its crusing.!!
is my old pci-ex slot in my mobo could be a problem??

Its not a gaming card unfortunately. I wont go and recommend some 200£ card but you would at least need a 6770/550ti to game casually and smoothly at reasonable settings. if you want to bump the graphics up to max at 1080p, a 7870 or 660ti are good mid range cards for around the 230£ mark.

Not sure. I think when it was a pci-e compatibility problem the card wouldn't work at all. But not sure though.

Did you install the latest drivers ? Did you do a clean install ?

The Ram isn't a issue.

What games makes it crash ?

Right, you said "crusing" not "crashing"