Is it okay to delete these file for space?

If that un-install file is put on by windows updates then the next windows updates it will look for it and create it again if its not there. I would suggest instead of going through folders and just deleting ones you think you don't need. I would go to start/control panel/add or remove programs, and look on there to see if there is any programs that you don't use anymore, or have never used. You can click on them and it will tell you the last time you used it. If you only have one hard drive installed it is not that expensive to buy a second hard drive or an external hard drive and just use it for added space. If you remove a file or folder and it messes up your OS then you will have to try a repair and it will probably add that file or folder back, if not its a new install and you won't have to worry about space anymore, since it will delete everything but your OS off the drive.