There are many reason to why your computer could be running slow but here are a couple of the most common options. There may not be enough space in the hard drive so erase unwanted material or replace with a larger hard drive. It could also be the size of the RAMS and you will need to reduce the number of programs running at the same time. It could also be your operating system, so check and see if it is running on Windows 10 and instead install Windows 7 which is much faster.