Lag in the normal window operations on my Acer Nitro 515-52

I brought the laptop almost 1 year ago and have not used it much because of the work load at office. I don't play games much on this laptop. But whenever I boot
every single operation is like slow. I have done following - removed unnecessary settings such as updates, cleared temp files, removed antivirus, defragmented, 
updates drivers but all in vain still for a normal chrome browser it takes 2 mins to launch.