Isn't there a setting in bios to enable 2nd processor chip?
Also or even more likely use msconfig and in advanced settings set number of logical processors to 2.
Sorry can't remember exactly but believe you will find the setting in there.
Run the system with the single processor, boot, then using msconfig/advanced options you should see the entry/checkmark space to tell it your using 2 logical processors. Shut down, unplug, install 2nd chip, reboot-correct bios-save, shut down, restart, cross fingers.
All this depends on the Pro version has this option as opposed to ultimate/business version.