I concure with Kane and Tarfu, the PSU is the likely source of the problem. if it was indeed bought back in september it will be under the initial warrenty. all you will need to do is file a claim with corsair as per
http://www.corsair.com/en-us/support/warranty

untill you can get an alternate PSU I again concure with Kane, do NOT power it up, prevent further damage to your system.

Tho you have stated.... it has been an ongoing issue effecting Sound and picture, so be prepare to replace your Graphics card soon. this is normal for PSU secondary issues.

I guess that's the problem with "building it yourself", you are on your own with trouble-shooting etc. if and when something goes wrong. That's why I personally wouldn't build a PC myself, just so that I have a warranty from one place and I can bring the PC to them and tell them "fix it, or else..." And they are like "or else, what?", and I am like "or else. I can't play my games anymore" and they are like "oh ok, we thought you were going to kill us or something, and then we certainly wouldn't be able to fix it" and I'd be like "Nah ah",