If that does not work:

Press CTRL, ALT &DEL at the same time. 
When the TASK MANAGER appears look for Rnaapp.  If it is there end task on it and try again.

If that does not work then try:

Right clicking the mouse button at the Start menu.  Click on Open.  Double click on Programs 
and then Startup.  Remove any unwanted programs that have to do with the modem. 
Reboot and see.

If it still doesn't work and you have WIN98
Then go to the Start menu and choose Run.  Type MSCONFIG and press enter.

Click on the Startup tab and uncheck everything but
 -scanregistry
 -systemtray
 -loadpowerprofile
 -taskmonitor
Exit and reboot

At this point if none of these fixes it, ask them to try it under another computer or format and reinstall
windows without any other programs and see what happens.