Windows 7 64 bit. The backup failed, error 0x80070020

OK, here goes: 

The computer is just over a month old, I just built it in December.  It is a 64 bit Gigabyte MB with AMD processor and 4 gb memory.  I have a C and D internal drive. I didn't have any problems with the backup procedure for the first three weeks and then it started.

The hardware drivers are all new.
No recent changes to the Computer in the last 10 days
I have NOT installed any CD burning software in the last 10 days.
I did install iTunes a month ago.
iTunes ran fine until a couple of day ago when a message started appearing:

"The registry settings used by the iTunes drivers for importing and burning CDs and DVDs are missing.  This can happen as a result of installing other CD burning software.  Please reinstall iTunes"

I ran a repair on iTunes (an option that came up when I tried to uninstall) and since that didn't work, I completely uninstalled and then reinstalled iTunes.  Still have problem.

Next I ran STC /Scannnow.  No problems found

Next I ran chkdsk C: /f /r.  No problems found

Next I ran the backup program.  Same error, The backup did not complete successfully,  Error Code:  0x80070020.


I went to backup settings and change them as the message suggested.  I UNCHECKED  "Backup data for newly created users" and the backup finished successfully. 

My question is, twofold, what the ____ is that option in there for and why are these kinds of things put in the operating systems AS DEFAULT items in the first place?


Looks like all is well and I only spent most of a Sunday resolving it.