IIS7 Joomla and Locked Files

[christopher_ham22]

I have multiple websites hosted on my server, and am having an issue.

 

Using latest release of Joomla and trying to install virtuemart however this keeps failing saying file cannot be moved. I have since discovered that whilst the world wide web service is running I cannot actually update any files in any site as windows claims the file is in use. How do i get round this?