HP Vectra VEi8 Supplementary Manual page 21

NOTE
Replacing the Pentium Processor (VEi8 models)
HP does not support processor upgrades. This information is provided
to help you replace a defective unit with a processor provided by HP
support services.
1 Remove the PC's cover (described in this chapter).
2 Remove the old processor.
a Open the retention clip on one side with your nail, then rotate the
processor with your other hand till it is free of the clip.
b Open the retention clip on the other side and lift the processor
out.
3 Install the new processor. Align the processor carefully above the
slot then push down firmly until it clicks into place.
Replacing the Pentium Processor (VEi8 models)