Sometimes certain keyboard keys doesn't work

Hello,

I Recently got Dell 3521 i3 Laptop but i have a problem with some keys Esc , a , Tab

sometimes they work sometimes not I tried to press them together for 5 seconds and

they are working again this solution works for hours but the problem come again after

restart or something idk what is happening hope some one got an idea to solve this

problem I tried Usb keyboard its working no problem and have dell driver installed

thanks in advance