I have a Dell Dimension 4100 with Windows ME which has a US Robotics 56k Voice PCI internal modem.  I've recently started getting the following message:

"TAPI Modem is not accessible.  Modem may be in use"

I can't figure out what is causing this problem.  I've gone into the device manager properties and see that it says "This device is working properly" and on the conflicting device list I see "no conflicts".  I typically have Winfax activitated with automatic receive, but am unable to use my faxing because of this error. 

We use a cable modem for internet and this, of course, does not affect that.  Some time ago we loaded software for a wireless router but I don't know if the timeframe of this problem would point to that as a cause of the problem.

Any suggestions for troubleshooting?  Thanks in advance for the help!  Please know that I'm not a computer expert, so put some detail in your answers for me.  : )