Dell Inspiron 1520
Intel Core2 Duo 2GHz
2 Gb RAM
NVIDIA GeForce 8600M GT 256Mb
160Gb HDD
Windows Vista 32bit
My Problems:
The first problem is that sometimes when I open the lid of my laptop the resolution sometimes automatically reverts to 1024 x 768 even though I repeatedly set it to the maximum resolution (1440 x 900). This also happens all to often when i minimise Guild Wars to get to the desktop. As you can imagine this is getting really annoying and after searching the net I have yet to find an explaination. This did not start happening until after my hard drive was replaced after it died on me

The second problem I have found to be a common one amongst Vista users with Nvidia graphics cards. Before having my hard drive replaced, while playing some games I would frequently have the screen freeze, go black, then after a few seconds come back. When this happened I would get the following message on the Taskbar: "Display driver nvlddmkm stopped responding, but has succesfully recovered"
After having the hard drive replaced, the screen no longer goes black but the interface of the game flickers and the colouring and textures of the game environment appear and dissapear rapidly and I have to press the windows key to minimise the game then maximise it again to stop it from happening.
I took a screenshot of the type of thing that sometimes happens although its hard to capture the fact that the windows (e.g. chat, guild window, party window etc) flicker and characters dissapear and reappear.

I hope this wall of text makes sense lol
Any suggestions of how to fix either problem will be appreciated...Thanks in advance
(No "you shouldn't have bought a Dell" replies please unless you follow with something useful lol)
EDIT: I'm unsure whether this is a hardware or software related problem so i just posted it here to get started, sorry if its in the wrong place