Can only conenct to wireless without encryption

I have a client with an Acer Laptop with an intel2200BG Wireless. He has three different wireless Routers that he uses. 1 at home, 1 at business #1, 1 at Business #2. He was having some trouble with the one at home having poor performance. I updated some of his plugins and did WIndows/Office 2003 Updates. I also unisntalled Clam AV and installed Panda 2006 Titanium.

I was unable to connect at all to his home router, even without encryption. I was able to conenct to his neighbor's unprotected though. I finally reset and reconfigured the router. Now I can connect without encryption but not with. I tried Business #2 and it no longer conencts there either (whereas it had no problem before).

I tried different channels at the home router, I tried netsumbler to check for interference... seemed alright although I'm not very familiar with the program.

I tried TKIP and AES on WPA... no luck with either one. 2 of the routers are Linksys SRX (MIMO) and 1 is SRX400 (Also MIMO). I have had very very very good success with these routers in the past.

It seems as though something is wrong with the laptop in regards to it's encryption setup...

Any Ideas besides F&R?...

I Forgot to mention that I also disabled Panda's auto protection in case it was somehow related.

i also have an acer with intel 2200bg and i had problems with poor encryption preformance, i solved it by using intel proset to manage the wireless connection instead of windows, works great ever since

It's very odd though that we have had very good success with that notebook and the same brand of routers and the Windows Wireless Managment with WPA until now.

Have you tried un installing the WNIC, then reinstalling it? Also check for driver updates for that wireless NIC. Also try deleting the wireless LAN and reconfiguring it!Had the same issues with a Compaq Laptop w/linksys WNIC! Just a thought!