W8 won't let me log in, have correct account information

I got a Lenovo Tab 2. It's running Windows 8 or 8.1, don't know how to see the difference from the login screen.

It was set up years ago to connect to my old wifi (before the lighning fried it), I set it up using my main Microsoft account e-mail address and password.

It's my standard Microsoft account, I use it every day for several other services so the login credentials are valid.

Now, years later I want to boot up the Tab 2 to upgrade it to Windows 10. I try to login but it says it's in offline mode. The e-mail account entered is correct. When I enter my password it says I need to go online. But how du I do that? The wifi symbol on the login screen shows available wifis, I have wifi password and everything.

What do I do? What are my options?

I got a Windows 7 x64 USB boot key that I tried to boot from to reset the OS to Windows 7 and upgrade from there. But I can't get it to boot from the USB. I enter the boot menu, it finds the USB, I select the USB, but the screen just... flickers for a fraction of a second and the boot menu is still there. Secure boot is disabled.

Can you temporarily change your router's SSID and password to the old one? This will let you log in and then you can create a new profile. After that is done, change your router back to the way it was.

TrustMe said:

Can you temporarily change your router's SSID and password to the old one? This will let you log in and then you can create a new profile. After that is done, change your router back to the way it was.

Click to expand...

Well, I was thinking about that as well, as long as I can remember the information, but I think I do. I wonder if I shared my phones and set it to look like my old wifi would work... Hmm...