Well, I have a very similar problem. But this not with a new USB card but a new USB laser mouse. It is a viewmate laser mouse. It came with its own drivers which I installed. Everything works fine but once it a while it hangs.
When it hangs the mouse doesn't move but all other button including the scroll wheel all work. If I simply unplug the usb mouse and then plug it back in, it works again. Any help in fixing this annoyance would be appreciated.
Also, another weird but perhaps related info is that this occurance is highly correlated with my cell phone ringing.

Yes, you heard me correct. Whenever my phone (sony ericsson) rings the mouse hangs. Although I have observed this I cannot say that this is the only cause or even if it is the cause at all. The mouse itself is a wired mouse so I'm not sure what about a cell phone might affect the mouse itself??
Thanks in advance for any help.