Lightroom 6 requesting license number after 6 years of being in use

Hi,

I have been hit with multiple problems after running Lightroom 6 for over 6 years.  they are as follows:

1. After having a new motherboard installed, I attempted to open LR 6 and informed me I was on a trial license.  Note two days before sending the machine to the shop for a new motherboard LR was working OK.

2. Attempting to reenter my product license number was a nightmare.  I dont fully recall the steps as I cant repeat them now because of the problem I note in point ().  However, roughly the steps were:

a. LR asked me to sign in via a QR code but I used the provided URL and did the following steps on my computer in which LR was open .

b. I logged in via the URL

c. Provided the security code and this was accepted

d. Went back to LR to complete the login but was asked to login again

e. Eventually I got locked out

3. I returned to day to try again but this time when I open LR and when I click the button to sign in on the Sign in dialog box (note at this stage LR has not opened), a mesage comes which says I need to "update your browser" and " To use Adobe services, please update your Adobe applications, operating system, and browser to the latest versions. ".  I cannot proceed past this point.

What is going on?  Help appreciated.