Mac Mini smiley icon/? folder

Hello, here is my problem.

When I try to boot up I get stuck at a smiley face/? folder. If I hit X or OPT I get to the drive selector screen (?) with a straight arrow and a circling arrow but no drives to choose.

Once in a while it will boot normally and run for a few days.

I suspect the cable is loose for the the hard drive/DVD drive controller but I hesitate to try taking it about to check.

Any ideas?

TIA

go into system preferences, and select your boot drive and select your HD
-chris

Do as couch says

You might try starting up in safe mode (press S) on start-up. If it starts up OK in safe mode you know your system or disk structure maybe a bit garbled.

Use ONYX to give your disk and system a complete overhall