Unreliable test running behaviour in VS 2010

I have a problem with unit tests hanging, without any visible result, i.e. even if I set a breakpoint very early in the unit test, like the first line, this breakpoint is not hit, and the test remains listed indefinitely in the Test Results window. Using the stop button doesn't change anything, and any subsequent attempts are running a test are greeted with a "Cannot start more than one local run" error popup.

Short of finding a low level hack into VS2010 to rudely kill it's test runs, what else can I do? Right now I end up restarting Visual Studio, a very timely affair.

NEW INFO: When I finally found a button somewhere on the test run view to show run details, I was rewarded with this surprising piece of information:

An error occurred while installing and starting the HTTP proxy used to associate tests with web requests. PRXY0022: When registering the proxy, another instance of the proxy was detected at end point '172.30.0开发者_如何学Python.30:3128'. Multiple instances of this proxy are not allowed for the same user on the same computer. (To override this behavior, use the 'AllowMultipleProxies' configuration option.) ASP.NET Client Proxy for IntelliTrace and Test Impact

That proxy address is our company's internet proxy.

I will certainly preserve with this problem, despite taking a short break now to seek a workaround.