There is a known Microsoft issue where applications using the WIN32_Service WMI class suffer memory leaks when running on Windows 7 or Windows Server 2008 R2. Using SQL Monitor, you may experience:

• Up to 1 GB of wasted memory on the entity you are monitoring. There may also be problems collecting data from this entity using WMI.
• Monitoring connection errors on the Configuration > Monitored servers page.
• 'Network path not found' or 'Out of memory' exception messages on the Log page.

There is a hotfix available from Microsoft to fix this issue. See http://support.microsoft.com/kb/981314.