About 6 months ago I bought a new router (Linksys E1000 v2.1) which worked great right out of the box. A couple months later I tried to setup a home network so that my two laptops could access a shared drive on my wired desktop, but for some reason they didn't show up as being on the same network. All computers involved are running Windows 7 if that matters.
Upon a recommendation from I friend I put DD-WRT on the router and it worked fine. Setup MAC filtering and WPA2 Personal security. This worked fine for about 4 months until today.
When I got home from work today I noticed my laptop wouldn't pull up any web pages, but it said it was connected. Then I noticed my iPhone wasn't connected either. I restarted my laptop and then it wouldn't connect to the wireless either (I could see the wireless, but I would get a Could not Connect error when I tried to connect to it).
I went to my desktop and it is working just fine, it is plugged into the back of the router. I also have an AT&T MicroCell (cell phone booster) that is plugged in to the back of the router and it works fine too.
I removed the encryption and MAC filtering, but that didn't help. I then reset to factory (or "factory" DD-WRT) and now the wireless works, but it is MUCH slower than my desktop. I ran a speedtest on my desktop and got 12 Mbps down and 1 Mbps up. On my laptop, I get 0.03 Mbps down and 0.25 Mbps up.