Tsk, tsk, tsk.....you can still run the computer I sent you & keep up all the updates till you get the software you want to install on it...at least for surfing, etc. you would be safe.
There is a feature to cleanup & optimize. Did you fragment the master file table (mft) & paging files, run file clean, empty recycle bin, check to see if there are temporary files not needed, etc.
If I were there, I would comb through to check what is cluttering it....