internet connection-disconnecting malfunction

I have a compaq presario computer 5070 series,20gig harddrive,56k modem Windows 98/4.10. AMD-k6(tm) 3D processor 92.0MB Ram,file system is 32-bit. I connect using dial-up,I usually have no problems connecting,but once computer has been connected for a long period of time,it won't disconnect. I use Callwave,and if an important call comes in,i usually well accept the call,this usually well disconnect me,but during these times,it won't even disconnect that way,I went as far as unplugging the phone line,and the computer remained on-line for about 10 minutes more before finally disconnecting,usually the only way you can get it to disconnect is just shuting it down,but then you lose whatever you were working on at the time.I run,adware,ccleaner and my spyware programs before i even connect to the internet,because other family members also use this computer.
Does anyone have any ideas why my computer does this and how do i fix it.
Thanks in-advance

 

Is there a setting/preference in Callwave that overrides your wishes to disconnect. If Callwave is to work integrally with your modem, it could be the culprit. I don't know, as I don't use such a beast, but those prefs are always a good place to start- no? Good luck.