cd /lib/modules/ find . -name "ieee80211*.ko" find . -name "ipw2100.ko"
Delete any modules/drivers found. IIRC, these are in the extra/ directory.
Go to ipw2100.sf.net, download, make, and install the latest version (1.0.1 at the moment). You will also need to download and install the firmware. The directions are on the site. Be aware that the firmware is closed source, binary only, and you will need to agree to a license. You will need the kernel sources to compile it. The new drivers will be installed in different place, "kernel/drivers/net/wireless/ipw2100/". You do not want to have two versions of the driver in the kernel modules directory tree.
My second suggestion is to check routing ("route -n"). If safe, take any firewall down. (I.e., do try this at home or work. Trying it in a coffeehouse/bar/dive where the hackers hang out can be hazardous to the health of your laptop.) Take any other network interface down, e.g. eth0. Try setting the IP address manually. Try pinging the access point. If this all works, try "traceroute google.com" or "traceroute 216.239.37.99" if you don't have DNS working.
HTH, Jeffrey
update did not solve still same problem