Calling all geeks, help - again!

I recently bought (on instalments) a new laptop featuring the wondrous new Windows Vista. Apart from a number of other irritating features, I have found that its Windows Explorer program - the one that opens file folders in the machine - is infuriatingly apt to crash. I do not know why it does that - of course - except that it always does so when I open certain document files, and that those files are very large - containing such things as films and music. Can anyone help me or suggest a forum where I might find help? It is an infuriating flaw that is seriously interfering with my use of the machine, and, needless to say, the Microsoft website is no help.