laptop slow

I've been having this problem for over a year. My Dell Inspiron 17 5000 Series laptop has been getting progressively slower to load. Also, once it does start up, everything is slow to respond to input. Opening an app, the browser, a notepad document, ect., can take up to a minute to open...

Hello, So i bought a new laptop a couple of years ago, it was a DELL 5521 but later on i bought a used laptop LENOVO X240. The problem is that the LENOVO X240 is better spec wise, but still it performs slower then my DELL 5521, I tried installing different Windows OS but still it performs slow...

The mouse cursor starts flickering and my laptop becomes very slow i have to hit F5 couple of time then it comes back to normal. Earlier it was like once every 3-4 hours but now 5-7 times every minute. I tried every thing- scanning for viruses, defragmanting the HDD etc. I even reinstalled...