My Zune...

For some reason my Zune wont run on my computer and I cant change the music or do anything with it. This really sux, It used to work before but now it doesnt. Does anyone have any idea why? Please help me if you do! Everytime I try to install the software it tells me microsoft has encountered a problem, I've tried to fix it but I cant. I have no idea what to do. Someone, please help!...