After you install a very old version of the SourceGear Vault client (v3.1.9.3798), opening a link in a new tab in IE 9 will hang that new tab. This is caused by the SourceGear Vault isntaller, overwriting some registry settings. I posted a similar problem on IE 8 [http://www.roelvanlisdonk.nl/?p=871], but that fix, did not fix the problem in IE 9.

I found my solution on: http://iefaq.info/index.php?action=artikel&;cat=42&id=133&artlang=en

Running the [ie8-rereg.all] fixed my problem.