|"If it is AMD athlon it supports upto 4 GB.."|
It's got nothing to do with the CPU. Memory support is dictated by the motherboard & also by the operating system. if you have a 32-bit version of Win7, there's no point in installing more than 4GB. If you have a 64-bit version, you can install as much as the board can handle.
"the motherboad is model WMCP61M"
That board is out of an eMachines - model & model number would be helpful. I did a search & I found that the EL1333G-01w uses that board. The max the board can handle is 4GB (2 x 2GB) DDR2-800.
"i wanna upgrade my ram in my computer for gaming purposes"
Hopefully you installed a gaming graphics card because you're not gonna accomplish much with the onboard GeForce 6150SE. And if you haven't already done so, you'll also need to upgrade the power supply. eMachines used low quality Bestec units which are not suitable to handle the loads of a gaming rig.
message edited by riider