turn the computer off
remove the power lead from the back
take the side off
remove the cmos battery
move the cmos jumper from pins 1 and 2 to pin 2 and 3 and the back to pins 1 and 2
replace the battery
put the side on
replug in the power lead
boot the computer
there can be 2 solder points you touch with a screwdriver
2 pins you touch with a screwdriver or use a jumper
a cmos clear switch or button
there will be a diagram and instructions in your manual
clear the drive with killdisk
then format and install
http://www.killdisk.com/downloadfree.htm