How get out of Demo Mode Win10 ??? Need help, please.

Hello,
Today purchased at Bestbuy open box Lenovo.
All the staff was very helpful and it came at a great price, so, this is not a complaint about Bestbuy.
Issue is that machine is in Demo Mode, which, of course, I ignored, as I installed about 6 programs. I use this machine for work, so, it's not a gaming fun thing--it's a necessary, I have to pay my rent, thing.
Questions:
1. How get out of Demo Mode ?
2. Any way to preserve the programs I've already installed, or will I have to reinstall?
Note: It's only about an hour or so to reinstall, so it's not really a big deal. More important is getting out of Demo Mode, and into the regular W10 user mode.

Your help would be greatly appreciated.
PS. Tried the search for "Demo Mode", and got links to Android sites, etc. So, don't quite understand how the search engine works on this forum.
Again, thanks.

I've worked with a couple of such computers and the only solution, also because of the password in them, was to use the OEMs Factory Restore process which wipes the partition then installs fresh. [1 was from Wal*Mart and process provided by them]

Could you kindly give me some brief instructions on how to do that?

The various OEMs do things differently so you'll need to check the Lenovo site for the manual for it, should have the instructions. I've done it on HP and ASUS.