I can't close my unity.exe ,so I can't open a project anymore!

I install Unity 5.6.0 yesterday on Win7 .
When I create a new project and the unity seems to create a process in my computer.
it doesn’t show any window on my PC,but i open task manager can see Unity.exe is processing.
I try many ways to close it but it still can’t close.When i want to open a project that i just created and i get the fatal error 'it looks like another unity instance is running with this project open. Multiple Unity instances cant open the same project.'So that i can’t open any project.I try to delete the file in temp but i a can’t delete it . I reinstall unity but it still have the problem. How could i fix it ? Thanks

Running on Windows, you can use Task Manager to stop individual processes, such as the one you’re encountering.

To solve your larger problem, start with uninstalling the Unity version which is misbehaving, then reinstalling it.

Edited: covering up reading comprehension failure.