Shift keys have stopped working for my lenovo flex3-15 laptop

Hello,

i have a 2 year old lenovo flex-3 laptop. a couple of weeks ago the screen crapped out, so i brought it to the local repair shop where they installed a new screen. now it works beautifully. got the laptop home and have now noticed that the shift keys no longer work. i could certainly use the caps lock to get cap letters, but that doesn't solve the problem of being able to use the symbols and punctuation above the row of number keys.

so far we've taken out the laptop keyboard to see if the connectors were firmly attached, and they are. then we reinstalled windows 10. after that i scoured the internet looking for ideas such as ensuring sticky keys haven't been activated and and ive even tried a strange approach of playing with the speech function because some website suggested this. no luck, i'm still unable to use the shift keys.

plugging in an external keyboard does solve the problem, and i probably like the feel of those keys better, but still the keyboard on the laptop should work properly.

has anyone come across this issue before and/or do you have any suggestions ....can't type a question mark at the end of that sentence.... just pretend there is one there... unhappy face....

many thanks in advance for any suggestions offered

windsor

ps - this is a touchscreen laptop, so i can use the on screen keyboard, but it's really really annoying