Sorry, i am find an a$$ load of .txt documents on my computer, if i delete all of them, is it going to effect to way a program will run, i think not, but just want to make sure.
Since this is almost an all n00bie thread, let me add some veteran advice
Mac OSX hides pretty much all critical system files from you. The stuff that isn't hidden, kexts and stuff need authentication to delete and they are in ~/System/Library/Extensions/ or ~/Library/Preferences/SystemConfiguration, places like that. Anything in your ~/User/name/ folder is pretty much safe, the one exception being the Library folder in there but even if you delete that, it's not going to kill anything, just delete preferences and such.