Go here and read through the X51-R1 Owner's Manual on how to open the case cover and remove the Riser Card assembly. Once done, follow the instructions below to "clear" the CMOS.

* Remove the power cord from the rear of the X51-R1
* Remove the Computer Cover and the Riser Card Assembly
* Locate the green 3-pin jumper (CLEAR CMOS) on the system board
* Remove the 2-pin jumper plug from pins 2 and 3 and fix it on pins 1 and 2
* Wait for approximately five seconds
* Remove the 2-pin jumper plug from pins 1 and 2 and replace it on pins 2 and 3
* Replace the Riser Card Assembly and the Computer Cover
* Reconnect the power cord and attempt to boot up