BleepingComputer.com: HP Notebook Monitor/Video Problems

Hello, I have a HP Pavilion dv6700 notebook running Windows Vista Home Premium with a NVIDIA GeForce 7150M / nForce 630M graphics card. Sometimes when I watch videos (especially large size files) my display will go completely black, and sometimes distorted. The sound will still play and in fact the computer still runs perfectly fine. The only way to get the display to normal is to do a hard shut down and turn the computer back on. Sometimes when I'm just surfing the net my computer will change my resolution to 800 x 600 instead of 1280 x 800 and change the program windows to the default color. Also in the Microsoft games (such as Solitaire, Freecell, etc.) the text is really huge and is cut off despite the fact that my DPI is set to default. Thank you in advance.