Dell OptiPlex 755 - Manual (Page 15)

Floppy Drive
1. In system setup, set the Diskette Drive option to USB.
2. Save and exit system setup.
3. Connect the USB floppy drive, insert a bootable floppy, and re-boot the computer.
Jumper Settings
Mini Tower and Desktop
Small Form Factor
Ultra Small Form Factor Computer
Jumper Setting Description
PSWD Password features are enabled (default setting).
Password features are disabled.
RTCRST The real-time clock has not been reset.
The real-time clock is being reset (jumpered temporarily).