PC restarts, mostly youtube, some games

Update your 5770 drivers.
Best method is to uninstall AMD CC manager first in add/remove
Then download latest CCC at AMD site.
Using Driversweeper is even better.
If that doesn't resolve your issues try updating Flashplayer.

I tried to update the driver but I forgot to remove to old one. So it continuously restarted itself. So with safe mode and driver sweeper I got rid of the old drivers. But I still can't get regular XP up, and when I go to install the new drivers in safemode it says it failed to load the hardware detection drivers! Any more advice?

Install gpu drivers as Admin.
Not sure what you mean by can't get regular XP up.
Do you mean it won't boot into XP only safe mode?
Sounds like your bios is messed up.

Correct, but it boots into XP sometimes then immediately restarts, or halfway through it restarts.

Could be psu or hdd related or even ram.
Do you have bsod screens?

I had had a few a while ago, but lately they don't appear it just restarts. The bsod concerned a hyper transport flood. As I said they weren't that common. Usually it just restarts.

Test your ram first with Memtest86+
http://www.memtest.org/
Make a bootable disk
Test each module one at a time
Some people say run it for 8hrs
i don't usually 30-45min will find any errors
If your ram is fine, make sure it's set at vendors spec for voltage
A voltage adjustment often corrects instability.
Let me know how it goes.

I a few other ram sticks lying around that I'll swap in.

Try not to mix different ram speed,timings,and voltages.
It will definitely cause restarts and instability.

They are all the same brand and model, and have the same speed, timings and voltages.

Maybe is overclocked CPU problem?

x2 on the ram, try one stick at a time and see if it boots, if one stick is bad it will boot but will crash when the systems needs more memory

You say games, what games do you mean ?

Like battlefield bad company 2

Download CPU-Z and post a screen of the memory and speed tabs as well as the CPU tab for reference.

From my overclock I came to realize a few things about BSOD and restarts. It's usually related to memory. You said you ran Prime95, but did you run it in blend mode? That tests the RAM really good. Let it run till it says you passed. It will either BSOD/restart there also or just fail and tell you it's a hardware issue. Since it's happening so quickly I would bet that it's a RAM config.

I already have CPU-Z, but it barely runs on safe mode, which is really slow now, I also don't have video drivers because they won't install.

I tried my other ram, which had worked before. No dice, one stick allowed to boot xp for a minute. I haven't played with the ram settings.

I'd start posting pictures of your bios settings or list what you have set for everything here for us to diagnose. It's gonna be a crapshoot otherwise.

I just noticed that my mouse still had power and the card reader LED's were on half brightness. It never did this before. Could it be a PSU problem?

PSU could be the problem with the restarts, but it seems like it could be the HDD as well.

I would clear your CMOS and then try booting.
Sounds like it might be a configuration problem within the BIOS, causing Windows to not talk to the Hardware properly.

I was getting the impression it was PSU overheating, so I put a fan beside my case and took the side panel off. It still restarted. But this time I got the BSOD, and once when rebooting windows it said a file was missing or corrupt and couldn't load windows. The next restart it loaded windows. As for the BSOD it says a crucial thread was terminated. Pics coming soon.

Maybe you also need to reformat your HDD and reinstall windows..just my opinion, a file might be corrupt in your system..