missing RAM and rstrui.exe file

I have a two problem question for one computer.
First my computer won’t save scanned in immages or run specific graphics programs (ie. Photoshop). I get a message saying I don’t have enough Ram to save/run the file or program. Even though I i have more than enough in reality. Second, when trying to use system restore I get an error message saying file rstrui.exe can’t be found in the winsta.dll library. Any ideas of what this could be?