Wireless Problems

Hello, I'm new to this forum, but I've been having some trouble with my wireless network recently. I use a laptop with intel wifi link 5300 card and Vista 64. Dell has not been any help, so hopefully someone here could help me. I switch between 2 networks everyday, (one at home, one in work). Lately there has been problems trying to connect. Sometimes it would connect without any problems, but it will stop working at random times, sometimes in a few minutes, other in an hour or so. It would sometime show no internet connection even when there is. Or it would show internet connection, but I can't access it. Whenever this happens, I can't get it working again unless I restart the wireless card on my laptop. This wasn't a problem before, but its happening so often lately. I'm using a TP-link with WEP and also a D-Link 3200AP with no password (couldn't set the password on it). Please help. Thank you.

I forgot to mention that the wireless router is next to the laptop and sometimes it would show no signal, then it would suddenly say the signal is excellent.