Kindle fire hd 8.9 Build.prop Utter fail. Help please.

[El Bonehead]

I screwed with my kindle fire HD 8.9 and now I need help. I will tell you everything I have done. I rooted my Kindle Fire HD with an app called Vroot and it lets you root without a computer. After rooting I then tried my luck with Rom Toolbox and started messing with Build.prop.. I messed with something like this ####m to make it run faster, I then changed it ####MB. I reset my Kindle and thats when it got bricked and now its just boots. It shows Kindle Fire System Recovery, and I tried to reset to default and it looked as if it were to work and then it reboots. I tried searching this up all over the internet and could find nothing. I ask if there were a way to change it with a computer but I need some one to help. I do not know what flash or adb is. Please Help