Vista - Problem With explorer not starting up and videos not playing but audio is.

Everytime I start my computer and log on my account I am faced with a black screen except for the white mouse pointer in the screen. I can load explorer.exe back using task manager however its quite inconvenient. For any fix on this please let me know. I looked at my registry and explorer.exe is in the shell.



Another problem I have is that any video on any video player will not work. I can hear the sound perfectly but no video. Examples of the players I used is DivX, Windows Media Player, Quicktime, and VLC. I'm trying to play a .AVI file but as previously stated I cannot see the video. If anyone has a solution to this please let me know.

Thanks for your time.