There is really no harm in staying connected (assuming you have DSL / Cable and you don't pay by the hour - and assuming you have a firewall to protect your PC).
But if you insist on disconnecting after a certain idle time:
- Right click on the connection icon on the bottom right of your status bar - near where Windows displays the time - (mine says Verizon Online, for example) and select Open Network Connections,
- Under Broadband, you will see your service provider (Verizon, Comcast, Cox, whatever)
- Right click on the Service Provider's name and select Properties
- Click on the Options Tab
- Click on the drop down menu of the second option from the bottom (Idle Time before Hanging up) and set the idle time that should elapse before disconnecting.
Fine Print; The above is for Windows XP. Other versions may be different.
IFruit users, sorry, can't help, get a real PC.
Use at your own risk. No purchase necessary. Void where prohibited.