so... i've been looking forward to having a dreamcast since it came out on the market... fortunetly i arranged to get one from a friend about 2 or 3 months ago.
the console worked fine since, no problems..
this day my friend has the idea to paint the dreamcast and i accepted it. so we opened the console and took all the boards/drive out.
days after we thought it was better for us and for the beauty of the console to keep it clean white, so we got to rebuild the system. what happens now is that the console's fine but the booting. it just cannot boot any cd and takes us directly to the main menu (game, settings, vmu, cd...)
it happens with any cd (music cd, backup cd, gd-rom)

i though it was bad connection of the drive but it doesent seem so! can anyone help me out?

EDIT: i might think the problem is that the cd/gd-rom gets refused when the console tries to boot. is it a board issue or drive issue? or connection issue? please answer as soon as possible