modem installation

Custom built computer.Mobo GIGABYTE GA7 VMM,900 MHZ CPU,128 MB Ram,20 Gig HD.CDR-W,DVD.Installed new modem MOTOROLA M56PCI with driver.WINDOWS detected modem,so does AOL,my ISP.Received error message:"no dial tone".Checked and rechecked connections.OK. Then :
1.-phone will work wherever it is connected to the modem(PHONE or LINE).
2.-Computer will not shut off and will restart by itself whenever the modem is installed.
3.-Get error message:"illegal operation...."In DETAILS it says:"WINKFTL caused an invalid page fault in module WINKFTL.EXE ast 01.7F:00404dea.
4.-Phone and all extensions work perfectly,and all waiting messages have been cleared.*70 is checked in my dial-up dialog box.
5.-It seems to me that thew modem hangs up when dialing because I do not get the usual full ringing sound.