Could you tell us what make and model your machine is?
Do you have any disks for the machine?
Do you wish to keep anything at all?
Let us know
Do you have any XP disks at all?
if you have XP Home we will need a home disk and if it is pro we will need pro.
Let me know
Could you shut the machine down and then power it up, However as soon as you power it up could you press and hold the Ctrl key and the F11 key till you get to the DSR menu.
Hopefully it will boot to the Dell Restore partition which will restore it to factory.
Try that and let me know what happens.
When it boots you should see a prompt that says press F12 to select boot device F2 to enter setup.
The keys must be pressed immediately after the appearance of the F2/F12 prompts.
Let me know what happens.