[qasdfdsaq]

First thing we need to do is get the modem's status while you're disconnected. You'll need to specify what modem you have so we can tell you how to get it's signal readings. Furthermore, you should try pinging the modem constantly, especially when it's 'down but not down'. I believe it's something along the lines of:

ping -t -w 1 192.168.1.100

in a command line or the Run prompt