i understand the issue and i see many more people had the same issue you can try these thing will help you for sure -
if your hard drive is almost completely full, your computer may run noticeably slower. You want to leave your computer some room to work on your hard drive. Follow our guide to freeing up space on your Windows PC to free up room. You don’t need any third-party software — just running the Disk Cleanup tool included in Windows can help quite a bit . i use this link and got my system fixed by acer help and blog click - [https://goo.gl/7VabqS|acer slow computer fix in simple steps] and also please uninstall
Uninstall unused/irrelevant programs
This leads to a reduced speed. It is good to uninstall such programs and let your computer breathe freely.
cut down some start up programs too they make you computer boot slow