Dave B beat me to it! If no-onbe has had the box open it is not likely to be loose cables - but you never know;-)

However. If for some reason, such as the battery running out, the bios settings have been lost you will need to rediscover your disks at bios level.

I don't know Dell particularly but the favourites to get into setup mode are F2, F10 or Delete. The boot up screen often prompts you.

Big 'BUT' here though. Don't mess with any of the settings you don't understand! If there is a bios menu item saying 'set bios to defaults' or some such - take it. Then go and check in disk drives or peripherals or whatever menu option it is to detect disks and do an auto detect. Once it can see the three disks (hard drive, cd and dvd) then let it boot up into windows. If you still can't see them - Yes you have a windows problem:-(

Hope this helps.

Cheers

Dave the Gnome