I don't have Phone Dialler installed, and it's not an option on my Windows components.
You can achieve the same thing with the hyperterminal - in Accessories --> Communications
You could also do a "Query Modem" from the diagnostic tab of the modem properties to make sure it is able to communicate with the rest of the world. You should get something like this:
ATQ0V1E0 - OK
AT+GMM - H.324 video-ready rev. 1.0
AT+FCLASS=? - 0,1
AT#CLS=? - COMMAND NOT SUPPORTED
AT+GCI? - +GCI:B4
AT+GCI=? - OK
ATI1 - OK
ATI2 - OK
ATI3 - TOSHIBA V.90 Data+Fax Software Modem Version 3.1.100
ATI4 - Built on 09/26/2001 20:12:19
ATI5 - 3.1.100, AMR Intel MB, AC97 ID:SIL REV:0x27, 0E
ATI6 - OK
ATI7 - AMR Intel MB
If the modem is faulty you'll get an error to that effect.
It is also worth removing the modem driver altogether and restart the PC - the OS should locate and re-install it automatically.
amofw