“I recently bought a wireless USB2 adapter which I use with my Linksys B wireless router. Strangely enough, when I restart, the computer detects it as 11mbps, rather than the normal 54mbps, any ideas?

As you have mentioned that you have a Linksys B wireless router – this product runs at the range of 11mbps. And remember that if your laptop/desktop PC are wherever plugged the adapter will be into USB2 otherwise the adapter will only work at 11mbps speed only.