Having trouble with Netgear Rangemax Wireless Router?

I had a Netgear Wireless Router 802.11. I used it for my desktop, 2 laptops, Xbox 360, and Wii. I also have the T-Mobile hotspot at home and could make calls through my router.

It was working fine until 2 weeks ago. I moved the Wii from our media room into the living room. The Wii could no longer pick up a signal and our cell phones would drop calls all of the time. I figured that the router was getting old, so I bought a Netgear Rangemax.

I installed the router last night. The desktop and laptops work, but the laptops move very slow on the internet. My signal keeps changing from excellent, to very good, to good. With the old router, the internet was very fast on the laptops.

Also, the Wii, Xbox, and 2 cell phones will not connect to the router. They can find the signal, but they wont connect.

I've made sure that the key is correct and also that the network I'm trying to long onto is my network. I'm using a WEP Security.

I'm not too familiar with routers, so any help will be greatly appreciated.