Sometimes you may need a telnet client in Vista or Windows 7. While in earlier versions of Windows they came pre-installed, Microsoft continued that practice.
To install, just open a command prompt and run: start /w pkgmgr /iu:"TelnetClient"
or if you prefer the more visual route:
1. Click on the Start ball
2. Click on Control Panel
3. Click on Programs or Programs and Features
4. Click on Turn Windows features on or off
5. In the Windows Features dialog box, select the Telnet Client check box
6. Click OK