2017 select lag

I used to use 2017 with no issues at all. one time in the middle of using the program it suddenly started lagging when I used the select tool. I lived with this for ages then got a trial of 2018 pro. I still had the same problem but found a patch for it. now I have gone back to 2017 as my trial ran out but have the problem again. I’ve looked at loads of other posts but don’t understand what people are saying.

I’m using: intel core i5 inside, Intel(r) HD graphics 520, Windows 10 10.0.17134, 8gb ram.