WEP is crackable in 2 minutes or less and can be a victim of a denial of service attack. Anyone that implements WEP can't complain as it's a well known issue.
WPA2 is better but sometimes you find issues. In our forum sticky we offer a well worn setup. I suggest you try it.
I am having problems with my D-Link DIR-615 Router. When I connect to the router, my connection speed to the network begins at 54 Mbps and over the course of 2-5 minutes it degrades to 1 Mbps and I am unable to browse the web. I have a Toshiba laptop with a integrated wireless a/b/g card, as does my roommate. We have no problems connecting and maintaining connection speeds to other wireless networks. Our service provider is At&t DSL service and are not having problems with the modem. I have upgraded the firmware. The two of us have Windows XP SP3. I have moved my router around to different locations and changed the channel that it broadcasts signal to 1,6, and 11 with no change in problems. It is configured with WEP and WPA2 enabled and is set to DHCP. I am being forced to repair my wireless connection about every 5 minutes to browse the web and have been unable to find anyone who has dealt with this specific problem and would appreciate any help as I've spent a lot of time looking through boards for a solution.