System Restore Incomplete, Shutting Down Problem

I have 2 problems :

1. I have recently installed a USB Modem for my Broadband mobile connection
(plug & play). What happens is after using the modem, I am unable to shut
down the computer in the normal way (I have to press the on/off button). Even
after I have disconnected and safely remove the hardware, for some reasons
the modem light is still blinking as if there is still connection. A couple
of times, the computer indicated that the hardware is in my F drive, when
there is none attached at all...
When I do not use the modem, my computer functions normally. I have tried
using the modem elsewhere and it works fine.

2. My computer' system restore is not working. How do I fix that?