|mmm without a disk of some sort... you are in a pickle...|
A full version CD may allow a few possible approaches/resolutions. A Dell OEM similarly... And a Dell recovery set would allow a couple of restore options...
Do you hear the drive spin up; do you see any actual start-up evidence (splash screens etc.); or evidence of boot-sequence?
If things start to some degree... can you get into safe-mode (press F-8 repeatedly during boot-sequence) to bring up start-up options?
Presumably too there are things (files/data etc.) on the drive you'd like to preserve? If so... perhaps wise to consider recovering/safeguarding those first?