I have bought a recon laptop for my son but it had no power lead, went to buy a universal one and it wouldn't charge.
I used to fix Compaq stuff for a dealer. A lot of those older laptops will not charge unless you use the official adapter that came with them.
This is what you need: CLICKY
There's 3 types available, make sure you get the right one. $23 is a fair price to ask.