helpful software for to use computer as mobile phone with out any internet

can we use our system as a mobile phone using just only a GSM SIM card of any network,and sure that we dont use any other mobile equipment and internet connection to our system,
if any one known the method please reply this

You have asked same question in two ways at eTI. Anyways, you can't use SIM in your computer with the help of just a mobile phone . However, if you have a GSM modem, then using some software (mostly supplied with that modem) you can make call, surf internet etc from PC.