Quote: "Dual-Core CPU T4200 @ 2.00GHz"
gpu nearly doesnt matter because fpsc dont use it to the limit, while it fully beats up the cpu (fpsc calculates the main graphic things via cpu, while using gpu only for effects

good for integrated gpu as laptops, bad for gaming machines and overall performance). 2ghz is very low for actual fpsc, i suggest a minimum of 2.4-2.6 to run it with good usable fps.
main thing is: build not that big levels. use nonstatics only where neccessary. trigger characters with triggerzones, not from the start of the game. stay within a max of 5 heightlevels at the beginning. dont build outdoor-levels without leveldesign-experience in fpsc.
lower lightmap-quality in setup.ini to 256/25.