Make sure you're using a supported browser; Firefox works the best. If you haven't done so already, clear the browser cache and try another browser.
That said, ISE has very strict requirements for VM specs and you are not using a supported combination of CPU/Memory. You meet the minimum for the Eval model, but ISE determines what 'hardware' model it is at boot-up based on the CPU/Memory values it detects. In this scenario, ISE will classify itself as an Eval model, but will not use the additional CPU/Memory over the 4 vCPUs and 16GB RAM.
You should shutdown the VM, assign the correct specs (including the CPU/Memory reservations) and see if that helps. The Eval model will be very low performance and can be slow to respond.
