Clearing/Removing MSN Live Messenger Chat logs/history

1. Open up Live Messenger:

• Tools > Options >Messages tab
• Uncheck "Automatically keep a history of my conversations
• Apply
• Re-check it
  

OR

2. Type in the Windows Explorer address bar:

C:\Users\UserName\Documents\My Received Files\MSN Username + random numbers\History

In your case, most likely:

• C:\Users\Username
• Documents\My Received Files\MSN Username + random numbers
• History
• Delete all contents of folder

On second thoughts, it might be easier to just use step 1.