Why do I get lag and low frame rates on games like N Ninja and Bowmaster even though I have a good computer?

On such games like Bow Master Prelude or N Ninja, I experience lag and low frame rates. I have a decent computer with three gigabytes of RAM.





Also, with these games that have a saving function, they do not save. I read it has something to do with the #savedvariables folder in my computer, but I cannot find it.|||maybe because ur computer is stuffed up or just ur eyes