Run IE as another user - hold down shift key the right mouse click then select run as another user

IE private browsing

InPrivate Browsing

You can start InPrivate Browsing from the Safety menu, by pressing Ctrl+Shift+P, or from the New Tab page. Internet Explorer will launch a new browser session that won’t keep any information about webpages you visit or searches you perform. Closing the browser window will end your InPrivate Browsing session.

http://windows.microsoft.com/en-US/internet-explorer/products/ie-9/features/in-private