Original post by: mayer ,
The question mark on startup means it can't find a system folder. It does not mean the hard drive is bad. The hard drive may have connection problems, a corrupted system or just needs to be introduced to the new things you have added. I usually do one thing at a time so that if I have problems I know where to look.I would start up from my system installation disk by inserting the disk restarting and holding down the "C" key. Go to the second page pull down menu and go to Utilities -> Disk Utility. See if it sees the drive in the left hand column. If so try repairing the drive and the permissions before restarting. You may find your problems are gone after this. If not and you did see the hard drive then restart and zap the PRAM by holding down the Command & Option & "P" & "R" keys. Wait for it to chime three times and then let off the keys.