I'll start at the beginning. As soon as I log on, I get a notification stating that I 'can't connect to the windows server' and this prevents standard users from logging in. Not really sure what this means, but it seems to have no impact on anything, I can use my PC as normal.

Update and Security - If I click this tab in setting - nothing. It freezes completely, can't click on any sub-tabs underneath, the window is blank, the only thing I can do is close the window.
EDIT: In setting, several of the other tabs just crash when I click on them, I can't do anything other than close the window.

Task Manager - Non-existent. If I press Ctrl-Alt-Del and click task manager - nothing happens. If I look under Windows apps and click task manager - nothing happens.

Java - I installed Java through Internet Explorer and have been getting notifications saying an update is due. I click on that - nothing happens. If I go to the Java website and try to update - the page crashes. I've tried to uninstall Java completely so I can then re-install the latest version, and the uninstall wizard crashes. After a while, I get a pop-up saying windows can't connect to the server.

Any suggestions as to why I'm having these problems? The computer is about 6 weeks old. Very frustrating.

EDIT: Another annoyance which may not be related to Windows 10 but if anyone knows why would also be helpful, when I power off my computer, it takes between 5 and 10 minutes for my tower to actually switch off, is this normal?