Computer Freezing problems - unable to boot/fresh install

Hello,

Been searching for solutions for a while and nothing has worked so i'm posting.

Decided to upgrade my build -

board = MSI 790FX GD70
graphics = 5770 card
psu OCZ = 550
CPU = AMD Phenom II X4 965 Black Edition
HDD = samsung 1tb
new ram = ballistix Crucial sport unbuffered 1333 PC3(4x4 16gb) (old ram 2x4 corsair)
New SSD = samsung 830 128gb.

after carefully installing ballistix ram and the samsung SSD the computer froze (booting off old HDD) on the windows startup screen, this has always happened with my build and a few restarts usually fixed it - but not now.

So i reverted to my old ram and unplugged ssd and it does the same but instead of freezing it restarts on the startup screen which it never did before.

I have tried booting win 7, vista (another hard drive) and win 8 install from cd, but they all freeze instantly including install which doesn't even extract.

So I tested each ram stick and this made no difference, it could not boot even on 2gb of ram. Cleared CMOS - again no avail, tryed system repair/revert (freezes) and now I am stuck.

A bit of history - the computer sometimes (rarely) used to freeze during COD4 and would require a restart so im wondering if the PSU is too low (550), the graphics card is faulty or the board itself. Maby its something like ram timings or voltage - which i have tried changing but failed as I don't have a clue what i'm doing.

Any help would be greatly appreciated,
thanks
Scott