Welcome to A.org :-)
If you turn the machine on and it doesn't boot from the harddisk (you see a animation of a floppy disk being inserted) that doesn't have to mean you don't have a fully functioning hard drive. On earlier model A1200s like mine, the machine doesn't wait long enough for the hard drive to spinup and so thinks it's not there. Get around this by resetting; press control and the two Amiga keys (the keys either side of the spacebar that have a sloped letter "A" on them).
