At our new house, we had to put our older desktop (Windows XP, 3 GHz processor, 2 Gb RAM) in a place too far away to hardwire with an Ethernet cable. So, I went and bought a USB wireless adapter to use with the new router that came with Comcast (dual 5.0/2.4 GHz). The driver loaded fine, and it says I have excellent speed (270 Mbps) and 5 bars reception, but the internet is slow and freezes up to the point where it is almost useless. What could be the problem, and can I fix it?