The top cover is loose

This has nothing to do with Classic. iOS is for iPhones, iPod Touch, and iPads.

MacBook Pros can't install either Classic or iOS.

There are several possible causes for the cover to come loose. And it really depends how loose. I'll be asking your post be moved to the MacBook Pro forum for further help:

http://discussions.apple.com/docs/DOC-2463

Taylor61356 wrote:

The top cover is loose on my Pro book. Has anyone had this happen?

Take in for a free assessment

Genius reservation http://www.apple.com/retail/geniusbar/

on-line https://getsupport.apple.com/GetproductgroupList.action

check warranty https://selfsolve.apple.com/agreementWarrantyDynamic.do