1 Copper

Dell Inspiron 15 5000 Series Keyboard issues. HELP!

So recently I bought 3 Dell Inspiron 15 5000 Series laptops brand new from for work.  I took 2 of them out of the box and i updated 1 of them to Windows 10 and left the other one with windows 8.1.  So I signed the Windows 10 laptop out to a co-worker to use.  Co-worker I will name BOB for this.  BOB came to me complaining that some of the keys on the laptop stopped working.  So I went and took a look at the laptop and sure enough the QWASZX keys along with the TAB, CAPS LOCK, SHIFT keys stopped working.  So I gave BOB the laptop that still had 8.1 on it and started trouble shooting this issue. I have had no luck finding an answer.  I turned the laptop off and set it aside while working on other issues.  Two days later BOB came to me and said the same issue is happening with the laptop I just gave BOB.  So I took it back from BOB and again started trouble shooting.  I have found this problem wit 3 different Dell Laptops all brand new.  SAME keys stop working on all three laptops BUT if I leave the laptops off for a day or 2 the keys start working again.  This seems to happen very randomly...Those certain keys work and then stop working and repeat.  Does anyone have an answer? I am tempted to the just return them and get something else.