Thanks for taking the time to check out the Windows Live Safety Center! We truly value your feedback and hope to hear more from you!
You brought up a very interesting scenario related to the identification of viruses that are currently quarantined by an antivirus application. This is something that we had looked at for our current release and decided to make the decision to go this way. We want to be sure to notify our users correctly of any viruses that exist on their system, whether marked as quarantined by another application or not. It is far better to be safe than sorry - especially when your safety and security is on the line.
This is a great comment, though, and something that we may take a look at for a future release!
Your second issue is something that we will definitely look into - it is our goal as a product team to ensure that you get a great experience while using our website and scanner - thanks for pointing this out!
-Bo Rohlfsen Program Manager - Windows Live Safety Center