|Did you recently rebuild the system (re-install the OS)?|
If you open control panel and then look under the system folder - hardware tab - device manager… you get a list of everything installed.
Look under the network adapters icon; do you see anything listed there - and if so what?
Ideally you will see things such as 1394 Net Adapter; Broadcom NetLink Gigabit Ethernet; and possibly an Intel® Pro Wireless 2220BG Network Connection. Those are what show on my elderly Acer 1692 laptop. What's in your Compaq may be a little different…
Regardless list here what you find under the network adapters icon.
Also note if there' are "any" yellow question marks (?) showing (anywhere).
Possibly you need to install drivers various; they can be obtained here:
Save them to your HD (somewhere safe ) copy to a cd and install from that.