I had a failed USB external HDD that caused the other USB device on the same USB header to disconnect when the external USB HDD was connected. In view of that, have you tried another USB port? If you have, then your MODEM may have failed.
thanks for reply.
actually the problem is with the front usb(4 ports). this happens only when i connect the modem to front ports.rear ports are ok.
the rapid storage tech. says device on port 0 removed and after sometime detected and this goes on.sometimes dvd drive hangs.this is very wierd problem.