Budget won't be a problem. I just want to know what hardware system should I upgrade it to and what hardware is compatible with windows 7?
Could I upgrade it to Intel® Core™2 Duo Processor E4300
(2M Cache, 1.80 GHz, 800 MHz FSB) ?
and the motherboard. what kind of motherboard that compatible with windows 7?
What's your motherboard? It may support the Core 2 Quad which is equivalent (almost) to the i5.
And You need to buy a graphics card instead of your integrated graphics.