Try to access the computer through Remote Desktop, Citrix, and so on.

If the physical computer or the virtual machine is still freezing, use one or more of the following methods for troubleshooting: For the computer that's still running in a frozen state To troubleshoot the freeze issues, check the current status of your computer, and follow one of the following methods. On how many computers does this occur? (Example: All computers, only one computer, 10 computers, and so on.).How often do the errors occur? (Example: This issue occurs every night at 7 PM, every day around 7 AM, and so on.).What operation was being performed when the freezes occurred? (Example: This issue occurs when you shut down GUI, perform one or more operations, and so on.).Which computer is freezing? (Example: The impacted computer is a physical server, virtual server, and so on.).Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products. The third-party products that this article discusses are manufactured by companies that are independent of Microsoft.

Windows 8 memory diagnostic