Try rebooting the router by unplugging it, waiting a couple of seconds, then plugging it back in.
For reasons I can't even fathom, the default settings on virtually every router out there are absolutely insane given the limited resources available on the router. A lot of the default settings don't even make a lot of sense if you're using a desktop system.
I don't know if you can change things like the TCP connection tracking options in the stock firmwares on Linksys routers, but most Linksys routers can have a custom firmware like DD-WRT installed onto them where you can.
Long story short, most routers are configured by default to keep a record of every single connection you make for like 2-3 hours. So when most routers only have 4-8MB of RAM, and that has to cover both the firmware to make the router do something useful, and everything else, it's very easy to run out of RAM which will cause the router to grind to a halt. Rebooting will clear these connections and let you get back to whatever you were doing.
Also, you really should update to SP3. Service packs should be considered mandatory installs.
today for example, I can hardly get online at all. And when I do it takes longer than dialup used to. I have wireless security key so no one is "bleeding" off me and also, I live out of town in the country about 20 miles. Ccountry.net is my ISP and no one is in the office today, big city, LOL! But, just wondering if this is typical of all ISP's that provide service to rural areas?
My pc info below:
MS Win XP
Service Pack 2
1.81 GHz, 480 MB of RAM
Physical Address Extension