I just bought this motherboard 5200 Athlon 64 X2 Dual Core Board Bundle + 2GB DDR2 Memory, You can find specs @ maplin.co.uk.
I also bought 4GB Vitesta DDR2 800MHz Dual Kit.
I cannot get the computer to boot with the 4gb RAM I Bought seperate.

The screen Stays Black, and the computer beeps like mad in a low pitch then High, I havent heard a computer beep like this before and i have put together quite a few over the last 8 years or so, im stuck any help would be great, Thanks

Have you listened to the pattern of beeps? Make a note of the pattern and check out the beep codes for your system online. Usually they're available in the manual for your computer that should be at the manufacturer's site.

You said that it does not work with the 4GB that you bought seperate, does it work with the 2GB that you got with the board. If it does then it could be the compatibility issue with the mobo and memory. Also try using one stick at a time and see if that gives you some positive results.