35w to 65w cpu, Can i do it?

Solution
Based on this:

Motherboard supports the following processor upgrades:
Core 2 Duo E4x00 with Dual Core technology (Conroe) up to E4400

No
Based on this:

Motherboard supports the following processor upgrades:
Pentium D 9xx with Dual Core technology (Presler) up to 960

Yes

You might need to update the bios, to support the new CPU, check your existing bios level and ask here or HP.

Note: If the bios needs updating to see the new CPU, you have to do it with the old CPU. But don't update the bios unless needed, because a bad update can ruin your motherboard.