Boot Trouble

[BamBooBoy2]

Here's whats happening- I've got my computer all built, and I've powered it up. Once before me and my bro booted it up and got into the BIOS. Since then I have turned off my computer and connected an extra DVD Drive, and plugged in two USB 2.0's, and connected the fan on the side of my case. Now I can get my computer up and running but it won't boot no matter what drive I select including default settings. I'm really at a loss for what to do, and if you need to know exactly what messages I'm getting or what hardware I have I can post that info.

Thanks

[shadowpr]

please post exact system specs, and what you have connected and what's not connected.

alos, can you at least get into the bios?