P5N-E SLI compatible GPU and PSU

[Xplorer2311]

Hi i have a P5N-E SLI motherboard with a Intel 2 Core Quad Q6600 2.80Ghz processor and a Asus Geforce GT 730 Silent 1gb Edition in it, needing a new PSU currently for some reason has 250w PSU for some reason but purchasing something around 500w or 650w, just wondering what is the best PSU to purchase and my main issue is im wondering what graphics card to get as at the minute it tends to black screen every so often, i was led to believe this was because the motherboard was so out dated but still unsure of a certain reason as to why its doing this, PLEASE HELP!!!

 

[Tradesman1]

Might be the PSU is the problem, a 730 calls for at least a 300 watt PSU....might look into something like a 500-520, like the SeaSonic S12II 520 which you could carry forward into a new rig. Then see how the current GPU does