Closing a dial-up connection can be done with just one keypress:
1/- Find RASDIAL.EXE in \Windows\System32\
2/- Right click on it and create a shortcut.
3/- Right click on this shortcut and choose properties.
4/- In the Target field, type space,/disconnect at the end of the path. That's normally:
5/- click once on the Shortcut key field and press the key combination you wish to have for closing connections.
6/- Apply, OK
Using an expensive ISDN dial-up connection, I make many short dialup connections a day. Using this key-shortcut saves not only time (a couple of seconds each time) but also some money on my phone bill.