Step by Step /system & /data backup?

Hello. Right. Though not completely computer illiterate, I would like some help on just how to replace my Intercept's original /system and /data files with some I found on the internet (the reason being that I suspect the original ones to contain at least one corrupt file - an educated guess based on some issues I've been having, namely a boot-loop).

So after a full system restore and what not it's back to perfect operating condition, but I'd still like to replace the /system files. I have the driver (downloaded from Samsung) and a .zip folder with the /system files. From here, how do I go about replacing the old ones with the new ones? Step by step, please. Note I am running on the stock kernel with 2.2 OS.

Thank you for your help.