In Windows 8, The Random Access Memory(RAM)/ Virtual memory will not be able to support all the processes. If you continue, you'll end up you Operating System. The problem can be fixed through following trobuleshoot solution.
Note: When you connect to internet, there are ads and malacious files that are automatically downloaded to your system program and alert you over and over prompting you with an alert "Low on Memory" and asking you to download programs. Ignore it, if in such case. Use good Anti-Virus software and activate shield for browsing.
It seems that you Operating System has build up with significant amount of (.tmp) files. Windows automatically delete the .tmp files but unable to relase completely.
1. Hit the Win logo (Start)> Type %temp%> Enter to open> Ctrl+A> Shift+Del(Delete All).
2. Internet cache: Open settings> General> View temp files> Delete all.
3. Task manager: Killing services is highly recommended. End services that you no longer use.
4. Free RAM memory: Right click on Desktop> Select new> Shortcut> Type %windir%\System32\rundll32.exe advapi32.dll,ProcessIdleTasks and type Memory. This will free memory. (This is for advanced users)
To get a solution and problem, you may want to try this option. Troubleshoot can't fix the issue but let you know what's the problem and how to sort out.
For this, press Windows logo + F> Type "Troubleshoot" (Without Quotes) in the search box> On the left panel, Click "System Maintanence" and wait for the result. If there's a problem, it will display the result of programs that needs to be fixed.