Startup And Operating problems

Hi all,
Sorry if it's a bit long, but more info is better. My mate and I built a pc about a year and a 1/2 ago and it was great. Good graphics card for a bit of gaming.
Now it's basically an over the top media centre, and ran well for ages.
Then the PC started to play up.

Here is the problem so far.
It had trouble booting past the bios screen and would get stuck on memory testing, the pc would just keep rebooting until it started.
When it did start it was fine.
Also at the same time the hard drive would click repeatedly.
One day the hd completely failed. The "clicks of death", they call it.
I got a new Seagate Barracuda 1Tb, as before, installed it, still had a bios reboot problem but the hd worked and i reinstalled windows 7.
Then the 42" LG plasma looked funny, the writing was very hard to read.
So then i found out it may have had a power surge.Probably did.
Windows 7 and apps were installed using a dodgy power supply, maybe the prob.
A new power supply, yet again pull out and reseated everything and change the back up battery and tested the 2 ram sticks individually, it now runs again, sort of.
At startup the screen has changed to the motherboard startup screen which is fine. That was because of the reseting of the bios. I had previously reset it in the menu and it sort of helped at startup so i decided to change the battery.
It now only reboots 2-3 times, sometimes straight away if it's warm. Most of the time 2-3 average.
It has a funny problem with ITunes.When your flicking through the playlist or using the slide bar will cause it to it just flick through all the songs or videos i have, automatically very fast, and you cant stop it.
If you quit ITunes then restart it, this won't fix the problem. You have to restart the PC and then it is fixed.Sometimes it takes 2 restarts.
This pc just runs the plasma and is hooked up to a huge Onkyo amp, with a million speakers. At the moment sound is just a 3.5mm jack out of the PC to AV plugs into the amp. Basic. Sound card soon.

Is the boot up problem a major concern?
Before i do a clean install of ITunes, 100gig and uninstall/reinstall ITunes, should i look somewhere else or do something else?
Thank you in advance for any help. I tried to include all the info i could.

And there's more.
Whilst watching an avi file, VLC wouldn't scroll through the movie. In the top left corner where it says VLC and the movie title, the text flickers.
Cant scroll at all. If you kill it and open anything else it is the same.
If you just let it play it's fine.
Media Player does the same.
Mp4's play fine under Quicktime.
ITunes was acting up.
Over the last couple of days, it seems to be happening more often.
I'm thinking complete reinstall of windows.
This is not a major problem, just got to remember to deauthorize ITunes.
Not much else on it as i just did it 2 weeks ago.
Am also thinking Graphics Card + power surge. Or is the graphics card getting too hot?
I checked for driver updates for the graphics card, they where ok.
I've attached the dxdiag.
Thanks for any help.
Andy.

 

no attachment with this...
As for reboots, automatic ones, none is best

There is no real mention of your setup. Maybe more details from the motherboard up would help with some ideas.

Personally, when software gets running funny I would uninstall and reinstall cleaning up files and reg entries as I go. But your issues aren't just software, it's hardware concerns as well.

 

Sorry, I thought i attached the dxdiag.
Will have another crack at it.