Did you upgrade your OS from Windows 7 to either 8/8.1 or 10?
If so, you may find that you may not be able to open the console to your virtual machines if you have hosts running ESXi 5.0. There is a very quick and simple fix for this.
You just have to download a newer build of the 5.0 client. Anything using the build 913577 or higher has already addressed the issue.
Here are some links (hopefully it will still be up):
- http://vsphereclient.vmware.com/vsphereclient/9/1/3/5/7/7/VMware-viclient-all-5.0.0-913577.exe
- http://vsphereclient.vmware.com/vsphereclient/1/3/0/0/6/0/0/VMware-viclient-all-5.0.0-1300600.exe
Another thing to note is that you may have to install this in compatibility mode.