I have the same issue, it was in the middle of an update and my computer restarted. After that it said:
"Curse Client v4 is not able to update itself to the latest version. The error is: The referenced assembly is not installed on your system.(Exception from HRESULT:0X800Y36BE) If you continue to receive this error, please uninstall this version, using the Windows Control Panel, then install the newest version from website."
I have tried to uninstall the program several times but it simply won't uninstall and if I try to just reinstall it I get the same error previously stated. So that leaves me completely stuck trying to get this to run sans a reformat/reinstall of OS. Also running win7 x64