I had a pretty terrible experience with Compaq myself. I couldn't get a Compaq Wifi card to work with my Compaq Armada lappy. When I called them they referred me to their networking group. The networking group told me its a lappy group problem. This went on back and forth and I never got it resolved. WTF can a product made by a company be completely incompatible with a product sold by the same company, especially when it comes to standardized Wifi drivers? It was ridiculous. I ended up chucking the wifi card and got a Linksys instead.
I have a friend with a Compaq Laptop, Presario, and it will not accept any brand of PCCARD wireless adapter. The system recognizes some; with Netgear it will not get past the bios boot screen due to a system conflict, with other brands it'll boot and drivers can install but the card will not actually work.
I think this is a motherboard / card slot issue and according to compaq is not a known problem so since the laptop is just out of warranty the friend is screwed. Well, USB wireless is an option... but... pccard slot is shot.
LAstly, there's an option for an internal wireless but also needs an antennae kit + installation, so pita. USB option is all I'm recommending.