How to Minimize Windows Live Messenger to the System Tray in Windows 7. By default, Messenger in Windows 7 minimizes to the taskbar, which in my opinion clutters up the taskbar and appears messy. However, you can easily make Windows Messenger run in the System Tray "by the clock" like it does in previous versions of Windows.
Make Windows Messenger Minimize to the System Tray
Right Click a Windows Live Messenger shortcut and select Properties
Select the Compatibility Tab, Check the Box to Run this program in compatibility mode for:, Choose one of the Windows Vista options, and Click OK
Next time you run Windows Live Messenger, it should appear in the lower System Tray next to your clock