Can you download CPU-Z from www.cpuid.com
and tell us what the speed of your RAM is, and the amount of pins if it is old.
The PSU supplies all the components with the juice for them to work, and cheaper PSU's do not supply enough amps on the 12v for it to work to its potential. Chepaer PSU's also die early, and when they do, they go with a bang, and you do not want to have to replace all the components affected in your PC.
Asrock is the low end of ASUS. And with Asus, I would go with A8N-SLI and above.
I would get a X2 in that budget, as games are already starting to support multi cores (Quake 4.)
You will need to format the HDD when you put it in your new system, so remember to back up everything.
Do you know of any sites that are in India?