Shoutbox

I was just researching it on the newgroups and found the exact steps on doing it.

a. If Windows Live Messenger is running, right-click the Messenger icon in
the notification area at the far right of the taskbar, and then click "Exit."
b. Open a Command Prompt window:
- On Microsoft Windows 2003, Windows XP, or Windows 2000, click "Start,"
click "Run," type "cmd," and then click "OK."
- On Windows 98 or Windows Millennium Edition, click "Start," click "Run,"
type "command," and then click "OK."

c. At the command prompt, type "CD\", and then press ENTER.
d. At the command prompt, type the following command, and then press ENTER:
CD %appdata%\microsoft
e. At the command prompt, type the following command, and then press ENTER:
CD "MSN MESSENGER"
f. At the command prompt, type the following command, and then press ENTER:
DEL /s ListCache.dat

Note: This command deletes all the ListCache.dat files in all subfolders.
You may see a list of the files that are being deleted.

g. At the command prompt, type "exit", and then press ENTER.
h. Restart Messenger.