New Power Supply needed, 500-600w, £45-£55, Help please

If the PC is the one in your signature, then a good 500W PSU is more than enough for your build. The XFX Pro 550W is a great deal: http://www.scan.co.uk/products/550w-psu-xfx-pro-series-...
Made by Seasonic, 5 yr warranty, quiet, rock-solid rails, 80+ Bronze while the Corsair is only 80+, less expensive than the CX600 yet higher quality and more amperage on the 12V rails....much better deal.

Thank you very much   I now have a 5850 but im pretty sure the 5850 only needs 500w psu