Vostro 3910 os reinstall

You can download the media creation tool at MS here and it will create a bootable installation flash drive. If you did/do not have a Windows 11 license from a previous Windows install you will have to purchase the license. However search YouTube as there are a number of sites that you can purchase the license from at a drastically discounted price and the licenses are legal and legitimate.

you can ony reinstall Dell installed OS for free, which is the meaning of re-install.  like JO said, if you Dell shipped Linux, there was never a Win 11 installed in first place.  so if OP wants Win 11, it would be technically a new install and not re-install of Win 11.  everything a/w JO.

It did ship with Win 11.  I got it set up and was going to make a restore point and mistakenly clicked system restore thing that would take me to where I could do the restore point.  Instead it instead it instantly tried to restore the system with a restore point wiping the drive.  Supposedly the product license is on the mother board so there is no license sticker.  I got the computer from Amazon and it is a foreign market one that is new but already out of warranty. I tried to install a Win 11 download but it needs a driver that this computer does not have.  Dell only supplies the Ubuntu download for out of warranty computers.  That is what I am using.  However it locked up while typing this so tomorrow it is going back.   I want an actual new US market computer.

Re:  Supposedly the product license is on the mother board so there is no license sticker.

correct.  the Win 11 oem key is embedded in bios.  you can actually retrieve it too.  

Re:  I tried to install a Win 11 download but it needs a driver that this computer does not have.  

Win 11 should automatically download all the drivers.  You can also look for additional device driver on Dell driver site.

Since you decide to return it, that is all good.  Hope the next one is easier to use.