It would help to know the make and model of your desktop unit?
1 - However, If you have a USB stick for example. You should just go to the manufactures website of that desktop for example, search the model, and download the driver to the USB stick ( on a working computer ) and install from USB and so on on the affected one.
2 - If its a custom build, you would need to know the motherboard make, Search on that manufactures site the same way (unless you have the motherboard disc), ie: Asus motherboard, go to www.asus.com and support, drivers and download it.
Its a long shot, Windows sometimes may auto-detect it in device manager and reinstall it, double click in the device manager (question mark of the device in question), or right click and attempt to scan for hardware changes. Perhaps it'll find it if it was installed once.