A saga of Windows 7, an m1530 and a Linksys router

This tale of woe begins with my XPS m1530, who is currently running Windows 7.  Everything's been working fine since the upgrade.  A couple weeks ago, I found that I couldn't connect with a wired connection, so being a savvy girl, I ruled out everything I could besides actual hardware failure, and had the motherboard replaced (since the NIC is integrated.)  Woot!  I had wired again, as of last Friday.  (That it may be irrelevant, but it was what happened directly before my wireless began its shenanigans.) I'm sick all weekend, and beyond a quick test of the wired connection, don't use the computer until last night.

So last night, I go to connect to the wireless in my apartment, and the first thing I notice is that my wifi light isn't on.  Since the switch sometimes gets flipped accidentally, I flipped it the other way... No light appeared in the darkness to offer me hope.  Huh, I thought, that's odd.  So I gave up and turned a light on to check the switch, and it was, in fact, in the on position.  Okay, I said to myself.  Maybe the lamp has failed.  Let's see if it actually sees the network.  It does.  So maybe It really is just the light - I'll connect to my network and it'll be fine. 

I hit connect, and it sort of thinks for a bit and then asks for the key.  The key is some ungodly string of alphanumeric rubbish - it's much easier to use a little flashdrive that has the Linksys software on it to sort all that out instead.(I'm sure there's a term for this kind of setup, but I don't know what it is.  <.<  >.> )  I get the drive with the key and start the Linksys software, which promptly informs me that my wireless connection is turned off and helpfully tells me to check my computer for a switch that will turn it on.  "...Wait, what?" I say.  I double check - Windows continues to tell me that wireless networks are available. 

The next steps I will summarize slightly:  Google for known Linksys/Win7 issues.  Find nothing that looks applicable.  Start futzing with the card.  Disable and re-enable.  Update drivers.  Update drivers in compatibility mode. Run diagnostics via the dell wireless utility.  Discover that they all fail!  Discover that it is said they always do that in 7.  Notice that the WiFi catcher also doesn't work - no lights at all.  Introduce head to desk.  Begin checking ever more unlikely things.  Install QuickSet on an off-chance.  Remember to check that everything is enabled in the BIOS as well.   Flail around helplessly.  Give up, have a drink and get some sleep.

I know there must be things I haven't tried, and information I've neglected to give you, so if you want to know anything else, just ask.  Suggest things.  I have this annoying feeling that it's probably something really niggly and dumb that's just slipped my mind utterly, you know?  I think if I can't find anything, I'm going to reinstall Vista, try and make it work there, which it should, and then re-upgrade to 7, since the settings obviously transferred fine last time.  But man, that seems like overkill, so I wanna see if you guys can bring some clearer thought to this. 

tl;dr - wireless works physically but isn't recognized by any third party software.  WiFi light doesn't go on even when switch is on.  WiFi catcher doesn't work.  Driving me a little crazy.