Why didn't you read the instructions of MS? They clearly told even at the download page that you should not install it on a working os. You should rather use another system where you dont lose anything. This is a beta version, even a demo version. It is just to evaluate it. It can destroy your old system, files, programs. That is why I installed it in a virtual OS. But the best solution is to install at a second unimportant system.

Better read instructions before you do something like that.

Currently you can probably only re-install Vista.

PS: I remember that you said you will change your avatar. It is still there with this flashing stupid animation.