Please help me I am going insane!
I have rooted me phone months ago and now I want to factory reset it, I know I can not do it since it is a rooted phone so I need to unroot it first but I don't know how to do it. here is the details for the phone:
Model number: GT-I9000
Firmware version: 2.3.3
Baseband Version: I9000xxJVO
Kernal version: 2.6.35.7-I9000XXJVO-CL182937 se.infra@SEP-51#2
build number: GINGERBREAD.BOJV9
I have rooted it using CF-Root-XX_OXA_JVO-v3.2-CWM3RFS.
here is the link I used to root my phone:
http://www.theandroidsoul.com/root-xxjvo-android-gingerbread-rom-on-galaxy-s-i9000/Please help me!

No, you don't need to unroot it.
Go menu, settings, privacy, factory reset. Untick USB storage!
Sent from ICS_TH_Build 15, stock kernel