Hi.
Well, a freeze by itself isn't a very telling problem, as there are numerous things which can cause it. The difference between the first and second freezes that you describe here is that in the first case video link is maintained, while it is lost in the second case. However, again, this isn't very telling as you're experiencing both.
The third scenario is a bit more useful, pointing straight to a .dll, but more information (perhaps a picture) about the bluescreen would help. If the computer restarts automatically and you don't have time to read the full blue screen, do the following:
- Go to Start -> Control Panel -> System
- Go to Advanced
- Under the Startup and Recovery section, click Settings...
- Under System Failure un-check "Automatically restart"
After a quick Google search, it isn't obvious that this particular .dll is involved in one error only (as it is often the case with .dlls).
To troubleshoot, (and this is a rule of thumb concerning problems in which you can suspect the GPU for any reason), I'd start by swapping the GPU for another one, which you know for a fact works, and is of course compatible with the system. If the problem still occurs after the swap, then we might have to dig further ^^