Nokia Cellphone as Modem- Port Open Problem Help!!

I have an Inspiron 8000 I bought new 3 years ago.  It has a 750 PIII with 128 MG ram, Windows ME. 

Ever since it was new, I've been using a Nokia 7160 cellphone as a modem choice when I am traveling and have no access to a regular phone line. This is slow but has always worked fine, given I have a decent digital signal.  The modem is inside the phone and the phone connects with a cable to the serial port. About 6 months ago, I started experiencing occasional problems.  Sometimes when trying to connect, windows would give me an error message saying the modem was not responding.  When doing a diagnostics check, it will show the OpenComm, port already open box or sometimes say the modem is not responding.  Until recently, I could either uninstall and reinstall the modem or defragment the hard drive and it would start working again for a while. But now that is not working.  I can defrag and reboot and reinstall, etc, and nothing helps.  Windows keeps saying that COM1 is already open.  I've tried control+alt+delete and closing all programs except the essential 2.  That did not work.  I deleted Palm software I thought might be interfering.  I've checked in the control panel and COM1 shows no conflicts.  I am at a loss for what to do.  I need to be able to get online away from home.  Please help!  (My regular modem seems to be working fine, no problems so far.)