I had the same problem due to a virus. I rebuilt my uncles medion 2030 laptop with XP home. I looked around and I was told the same as you, get the drivers from the Medion website. Done that but no network controller, so the wireless didn't work.
Every website I went to told me that the spec for the wireless, was a Prism 3886 802.11g wireless made by Intersel Americas, after downloading it, It would not let me install the drivers. Obviously because it wasn't a Prism.
After a week of pulling my hair out I finally cracjked it.
Hope this is of some help.
Go to the following website http://halfdone.com/
and download the unknown devices file.(UKD). Unzip it and then run it, this will tell you the name of the device that you are looking for, if it doesn't look under Computer missing names. That is where I found out that I had an Intel pro/wireless 2200BG installed.It willalso give you the names of anything else you don't have a driver for. The rest was easy, went to Intel and downloaded the correct driver and installed it. Works a treat, I can now give it back to my uncle.