Performance Preferences Won't Open

Has anyone ever had issues opening the performance option in preferences? Every time I try to open it, it gives me an error message that says I must enter an integer between 8 & 50. I click "OK" like a hundred times. It never opens. What can I do? I was having issues with not enough RAM, so I switched the scratch disk. It worked for a while, but it is still running very slow and wont perform certain tasks or save files. Everything I have read online, says to go to performance and adjust options to fix the issues... Can't do that when it won't let me open performance preferences. I ran a disk clean up and have uninstalled and reinstalled Photoshop, and it's still not working properly.