Newb problems

[FML1990]

Right so I'm new to overclocking, and have no idea where I start despite reading the intro bit.
What are generally considered safe temps for CPUs and GPUs?
Also how far do you think I could push my set up currently?

 

[FML1990]

Anyone suggest a decent one then before I come back on and you all tell me I've got another crap one ha.

What's your opinions on factory refurbished stuff? I can get my hands on a corsair 750w pretty cheap at the minute.

 

[FML1990]

Many thanks.

As for the comment on my PSU, I only have a 750W because my old one blew after 2 days of it running properly and I got given it as a replacement.