Recently (since sometime shortly after 2012-05-01), my USB wireless adapter (Realtek RTL8187B according to Device Manager) has decided that it will start dropping almost all of my packets whenever I use the Switch User screen. This begins as soon as I press Switch User from the Lock (windows-L) screen or from the start menu, and continues whether I switch to another user or switch immediately back to the original user. Whatever is causing this does not affect the ethernet connection I have to my local network (which is not connected to the internet and has no gateway). Just locking the computer does not trigger this problem.
Once the packet loss begins, the only way to fix it is to open the network interface list and manually disable and enable the wireless adapter. The "Diagnose" command detects no problems with the interface and won't reset the adapter for me (I guess one or two packets getting through is enough), and the taskbar icon for the wireless connection shows a full signal meter with no problems.
I don't see any patches from around that time in my Windows Update list, and I went on vacation and came back to this problem. Any thoughts on what could cause this, and what I can do to troubleshoot it?
Tested using a cmd.exe window running
ping -t gatewayip and looking at the number of timeouts after switching back to the first user.