Problem installing

i am having a problem trying to install horizon again i made sure to get rid of all the other horizon files and it the error says "0x80070660 - the temp folder is on a drive that is full or is inaccessible. Free up space on the drive or verify that you have write permission on the temp folder " so i was wondering

  1. what does this mean
    2.what is a so called " temp file "
  2. how do i solve this

this is for the newest version of horizon any answers are helpful to me and thank you