Didn't remove factory screws fron top of CD player

Oops! Don't feel bad, even us experienced installers have made this same bone-headed move. Unfortunately, not having been there, can't really say what the problem is. Look in the manual to see what the "error code" means. However, I can't imagine any manufacturer designing a unit that would be damaged by inserting a CD whilst the transport screws are still in the unit. You might try looking for the reset button/switch, or removing the power from the unit for a few seconds to reset the logic circuits. What scares me is the "thump" noise. No telling without a physical look-see.....Clean tools = Clean work!

Great thanks...I had previously hit the reset button, probably 15 times hopeing it would do something. Disconnected the power, plugged it back in, hit the reset button and it works fine... thanks again.I am confused

Glad I could help, although you would have eventually solved this problem automatically by taking the unit out to have it checked, which would have entailed disconnecting it. Then (maybe $20-50 later), the service tech would have told you "nothing wrong with it, works fine!"Clean tools = Clean work!