My laptop is not starting

My Dell Inspiron N5040 laptop will not turn on. It is coming up to 11 years old (I know, it’s old) but worked fine if a bit slow before recently when this problem arose. It is not the CMOS battery, and I only just took it apart and cleaned it thoroughly a couple of years ago, and reapplied the...

Hi, I have a Asus rog gl553vd series laptop. I didn't used it for a week n didn't charged it. I tried charging but the led is not on n I tried pressing the start button nothing happening, so what should I do.