Take everything out (carefully) and then put it back together(carefully). When you do it...forget everything you did the first time, try not to just copy your procedure of installing stuff. that will lead you to making the same mistake you already made, unintentionally. I would just start by putting in the cards such as vid sound and nic then put in the hard drive floppy and cd rom. Make sure its all connected right with ide cables in the right spots and everything. Hook your hard drive to your led. Reassembling often solves many problems. If you get too frustrated go to bed. I have messed my computer up so bad thinking i would have to buy new components, only to think of a new idea the next day and fix everything.!!! dont worry be HAPPY