The Dell Service Tag is important to the Technicians because they may need it to order replacement parts from Dell to fix your computer.
If your desktop computer will not power up to get the machine name, the Service Tag can be located on the left hand corner of your computer's hard drive.
The Service Tag is always 7 characters long - consisting of letters and numbers. No dashes or special characters.
OR on the back of the computer located on a white barcode:
For a laptop, this is located on the bottom of the machine, in small letters next to the words, "Service Tag".