Ok, thanks for your replies guys - Mobo = Asus M4A77T, with an AMD PhenomII X6 1055T CPU, along with the other weak point of the setup - an Octigen 400W (Model# 116196PostGatx) PSU. The total output power Max is rated as 379W - over the +3V, +5V, +12V (rails?), and total output of the +3.3V and +5V "shall not exceed 235W.
As obvious I'm not a whizz when it comes to PSU's and the power ratings etc! -
This is actually a backup PSU I had to bung in after a so called "repair shop" who shall remain nameless until I've confronted them, managed to format a HD - with FAT32 for some reason - and nick my Enermax 425W Modular PSU! (= 1st and last time I EVER take a PC to a so called repairs specialist! - Only did it 'cos I was ill, and not thinking straight!)
OK, rant over - think from a quick scout that I've had that a £50 or pref' sub £50 should get me what I need - but you guys know alot more than me!