What are your computer specs? Sometimes having not enough memory (RAM) can cause Windows 10 to hold up. I'd say if that is the case you should have at least 8GB.
Is Windows 10 genuine? I'm assuming you downloaded W10 over your old OS which can sometimes carry over viruses. So that's also a factor in this case.
In addition, are you able to access task manager and tell us what's running i.e. CPU Usage & RAM Usage