• I concur, first step is to remove enough data to keep the hard drive no more than 70% full. After resolving that then look for other issues. Note that overfilled hard drives will slow down operation and can lead to serious instability.
• Newer app and OS versions are utilizing more and more RAM (after all, RAM is now cheap). Browsers can be surprising RAM hogs, some versions worse than others. IMO most laptop users will benefit from max RAM.
• Hopefully you have not loaded any free or pirated software, because such apps frequently come with malware embedded.
Good luck!
-Allen