After some attempts, I got to know that the solution was in Scheduled Tasks and not in Start-up folder or the registry. When I made some efforts to disable this, I didn’t find any workaround. Recently, I was pissed off by receiving Apple Software Update pop-up, which frequently appeared on my computer only to tell me that I should update iTunes, QuickTime and iCloud. And this time also we have come up with possible solutions. Now, similar problem has cropped up on Apple software update screen on Windows and Mac running on OS X. There were many complaints from users about this, and therefore, we worked around this issue and found solution.
Sometime back, we have dealt with an issue of removing software update download from iPhone/iPad.