Frequent multi-colored crashes

Basically My computer crashes whenever running some sort of application such as minecraft, or even Youtube, and it also crashes at random as well.

I have a 64bit Windows 7 OS, Radeon HD6870 GPU, AMD Phenom II CPU x4 855, WD 1tb HDD, Corsair Vengeance 8gb RAM, an OCZ 850w PSU, and finally a disk drive.
I have tested my HDD many times and i'm pretty sure its not infected in any way.
I also recently returned my GPU for a new one which works a lot better than the last one (Which was broken) so im inclined to believe that that is also not the problem.
I have updated all the drivers of all my devices,
I have scanned my computer with Malwarebytes, Avast!, TDSSkiller, and even OTL
and only found one Rootkit that i'm pretty sure i dealt with and it is gone.
I am deeply confused and saddened by my computer's sickness and would greatly
appreciate any kind of advice or help of any kind.
Thanks Again!!!

When attaching dmp files, PLEASE put them in a single zipped folder

Originally Posted by papamidnight

Basically My computer crashes whenever running some sort of application such as minecraft, or even Youtube, and it also crashes at random as well.

When you say crashes, do you mean bluescreens? Freezes? Just goes black?

With no details of your system etc. we haven't a lot to go on. You're best bet would be to follow these instructions usually handed out in the bsod forum. The more we know about your system the better chance we have to help.

To ensure minidumps are enabled:
Go to Start, in the Search Box type: sysdm.cpl, press Enter.
Under the Advanced tab, click on the Startup and Recovery Settings... button.
Ensure that Automatically restart is unchecked.
Under the Write Debugging Information header select Small memory dump (256 kB) in the dropdown box (the 256kb varies).
Ensure that the Small Dump Directory is listed as %systemroot%\Minidump.
OK your way out.
Reboot if changes have been made.

The .dmp files are located at C:\Windows\Minidump. Until a .dmp file is generated, the Minidump folder may not exist.

Please see: How to ask for help with a BSOD problem Following Method 2:
Download and run the SF Diagnostics Tool. Right click the SF Diag tool and select Run as Administrator before running. When the reports have been created, zip them up and attach to a post.

Download and run CPU-Z. Take screenshots**/snips of the CPU tab, Mainboard tab, Memory tab and all the slot #'s under the SPD tab.
Go to Post Reply, click on the Go Advanced button and attach the screenshots**/snips to your post for all the RAM experts to see by using the paper clip you will find on the top toolbar. Do not zip them up.
**If screenshots, please crop.

Also see: Help Us To Help You By Filling In Your System Specs.