>I installed Windows XP (on an old computer). The computer used to have wireless connections so there must be a wireless network adapter. But when I go to Computer -> Manage -> Network Adapters I see:
>1394 Network adapter
>Bluetooth Device
>but no Wireless network adapter.
>Is Wireless network adapter I have to install from some utility disk that came with the computer? What am I missing?

If it's a laptop then almost certainly yes it has wireless built-in. It probably is showing as an unknown device in Device Manager and needs a driver. You'll either need to install it from a utility disk (e.g. Dell) or download using another computer and transfer via USB stick etc.

If it's a desktop computer, it may no longer have a wireless adapter (typically in an expansion slot), it might have been pulled to be used in a newer computer.