computer no longer recognizes wpa encryption??

The problem: The wireless setup at my home uses WPA encryption. My laptop no longer recognizes it as far as I can tell, but it did before.

Setup:

Cable modem internet; ISP Comcast
Linksys router - BUT running DD-WRT
3 computers in network - 2 desktops, both custom built (one running Vista/Win7 and the other XP) and my Toshiba laptop - XP Tablet Edition with SP3
The desktops are connected with ethernet cables; I (usually!) connect with Intel PRO/Wireless 3945ABG adapter. My IPod recognizes the wireless and connects, as does the Nokia N95.

The wireless worked fine until last night. We were gaming and the game kept dropping me, so I wanted to connect with ethernet. We took an extra Belkin router and set it up between one desktop and me to act as a switch, since we only had short ethernet cables (less than 5 feet) and they wouldn't reach from the Linksys router to my laptop. I also ran CCleaner just after getting the ethernet hooked up and functional. We played the game, yadda yadda, but after when I tried to hook up to the wireless, a connection failed to form. I shut down my computer for the night and am trying again this morning. When I start up, the wireless tries to get a connection. First, it gives me limited/no connectivity, with a 164.x.x.x ip (useless). When I click on "View wireless networks" it tells me that no wireless networks are in range (which I know to be false). This is especially false, since my computer is constantly trying to obtain an ip from the wireless.

Things I have tried:
-rebooting
-repairing connection
-updating driver
-disabling wireless, walking away for a while, and re-enabling
-in CMD, ipconfig/release then ipconfig/renew (error: cannot contact DHCP server)
-ipconfig/all verifies that my DHCP is on, as is autoconfig
-If I click on the icon when the connection is limited, it says under the support tab that "You might not be able to access the internet or some
network resources. This problem occured because the computer did not assign a network address to the computer"
-also in cmd: netsh int ip reset reset.log (followed by) netsh winsock reset catalog (followed by reboot)
-Restarting computer browser, dhcp client, and workstation in services.msc

The reason I think that my computer is failing to recognize WPA encryption is this:

start>network places>view network connections>(right-click wireless and choose properties)>wireless properties tab>(under preferred networks)Add

In this screen, there are only two options for data encryption: disabled, and WEP. My computer has successfully used WPA for several years now and I fail to see any reason why it would not be an option any longer. Perhaps I'm on the completely wrong track, I'm not sure.

Any help is appreciated! Thanks in advance :)