Check you are not low on disk space. Download and install the free version of malwarebytes. Update it and run a scan. I'd also run a full anti-virus scan. After these, use msconfig to see what programs and services are starting up. Ensure that a defrag is not scheduled and running on a regular basis. Use Task Manager to see what process is using a large amount of memory. Search on the internet to see how to do all this as there is no time or space here for me to do it. It might be worth reporting back to tell us how you get on. Good Luck!