I assume that many of you, like me, have had their Dell wireless 1390 series mini pci cards fail on you:

I had much the same problem: nine months ago, the card in my inspirion 1521 stopped working properly; the led wouldn't come on, and the wireless card could not be seen in either the device manager or the BIOS.It continued to work sporadically until five days ago when it failed entirely.

 

SOLUTION: it turns out that the WLAN port that the card was seated in had burnt out. I simply switched the card so that it was seated in either the computer's WWAN or WPAN ports. I've yet to see if it can actually connect to the net, as all networks in the area are locked, but my computer does recognize the card, and it can detect networks, so it seems that for now the solution works. I hope this helps others who are in the same conundrum as me

 

sincerely, Alex.