My Surface Pro 3 isn't working correctly. PLEASE HELP!

[Windows Central Question]

A few days after installing Windows 10 on my Surface pro 3, my computer reverted back to an old style computer. On my keyboard, nothing happens when I left click the mouse to open the windows icon on the taskbar. When I right click on the window, any old style shut down appears. Also, my previous windows screen with apps has vanished. Cortona doesn't appear. The Edge icon vanished. On the task bar, I can't open new notifications when I right click...In other words, something is very wrong with my system. Please help.