1. open computer
2. remove all drives except for your master hard-drive
3. remove all network cables
4. boot
5. shutdown
6. put CD-drive back in
7. reboot
if that doesn't work open up the bios menu when you boot-up, and fix the problem in there, if the disc drive isn't even recognised in there, then you'll need an computer technician
I type as I speak, with several commas and run on sentences, dont be hatin'.