please post here if you still can't get back on after the recent updates, describe your issues.
Latest attempt within the last hour. clean install of win7 in virtualbox with default settings (1gb ram), fresh download of setup file. Client installs, when opened for the first time prompts 'client software must be upgraded', press ok, client begins to install. Goes like this; 'preparing to install...' requests admin access (press ok), 'please wait windows configures...' and it quickly disappears before the bar fills, when i attempt to run the client this process repeats.
Second attempt using the same install of win7 with the ram turned to maximum possible (1954mb) and network adapter setting changed to 'bridged adapter' as per nomnomnom's suggestion; uninstalled client in control panel, reinstalled using the same setup file. results were identical.
I hope that helps a little bit.