Try the procedure described in the following MSKB article:
Q324760 - "Error Message: Error 633 Modem Is Already in Use"
Trying to unweave, unwind, unravel
And piece together the past and the future,
T. S. Eliot
I connected my windows xp Toshiba satellite pc to the internet via a dial up connection and it worked with no problems. But after the connection was cut (phone line problem) and I rebooted the pc, the dial up stopped working. I get message 633: com port engaged or used by another program. I can't find which program it is, plus, I tried to use toshiba windows XP help but when I see if my COM port (3) is enabled, it isn't even listed anymore. A search to add new hardware finds a com port 5 but that isn't right. And when I try a diagnostics query modem it says there might be a hardware conflict. However, windows says the modem is working when i go into modems.
Any suggestions for getting the com port 3 open or any workaround to get the dial up internet functionning again?