my friend put a cd player in his car and now it just turns over and wont start and advice

 

uhh thats odd. I don't know of any reason why it wouldn't start. Unless he unplugged something on accident.

 

I seen this before..... It is when someone decides to blow one of the main fuses during a bad install.

Pop the hood, and check the fuses inside the engine bay. The big ones, and the square ones. He probolly blew an ignition wire fuse, or fuses.

 

Yup, that sounds right.

 

any chance you might've drained the battery during the install??
Listening to loud tunes for a couple of hours with the car off?

 

He said it turns over so thats not an issue.

 

not really...
A half dead battery will turn over but the car won't necessarily start.
If you get a chance take the battery to your local autozono/pepboys/midas/etc, to have them do a quick checkup...