We yet don't know what you're overclocking for.
Your current processor is running at 2.33GHz and you are expecting an overclock of 2.5GHz~2.9Ghz. In all likelihood those frequencies are minor to say the least. Going any higher and you risk killing your system merely because;
a| you don't have aftermarket cooling
b| your motherboard doesn't have adequate cooling for the VRM area
c| your system, judging from the specs, is aged and time might have taken a heavy toll on the innards thus the system is unreliable for any strenuous activities to say the least.
It would be best to get a new system altogether and try your hand at overclocking. I'd have suggested getting a better GPU but anything you'll put in it will be bottlenecked and...