Standard Windows XP installation media does not come in WIM format; it uses a text-based setup. To create an XP WIM, you must "capture" an existing installation.
You can "mount" a WIM file to a folder and add drivers, security updates, or software without ever actually booting the OS. How to Create a Windows XP WIM Image windows xp wim
Because it is file-based, a single WIM image can often be deployed to computers with different hardware configurations. Standard Windows XP installation media does not come
Use a tool like ImageX or DISM (Deployment Image Servicing and Management) to capture the C: drive into a .wim file. windows xp wim