Hi:

I tried installing the TEW-441 WinXP drivers off the CD.

ndiswrapper -l shows:
net5211 driver present, hardware present

iwconfig wlan0 essid "MYNET" mode Ad-Hoc shows:
wlan0 No such device

I have tried removing and reinstalling it, after a reboot, tried removing and rewriting the line from /etc/modprobe.conf, still no success.

One thing is to make sure it is plugged in all the way. Also go to System > Administration > Networking. It will show up there if it exists. Do your lights turn on?

Anyway, if all those fail, you didn't fully install the card. You should do this...

ndiswrapper -i (driver name here)
ndiswrapper -l (you should see "Driver Presant, Hardware Presant")
modprobe ndiswrapper (your lights should turn on now)
System > Administration > Networking (now enter your ESSID & WEP code, hit OK, and your done!)

If that fails, try searching google for "Trendnet TEW-441PC linux" and you should get some help that way.