Hello,
I'm your Independent Advisor for today. I know this can be frustrating, but don't worry. I'm here to figure this out for you.
Please press Ctrl + Alt + Del to open Task Manager. Then click "Run new task" and type in "explorer.exe", click OK. Your desktop should appear. Kindly test it out to check for issues.
Also, based on your description, it seems you installed Windows 10 to another partition, hence asking you to choose between Windows 7 and Windows 10. Did you mean to do a clean install of Windows? If so, you should have deleted all partitions and then continued with the install.
Hope to hear from you soon.