Head over to this site. They deal with the "Access denied" issue:
http://www.windowsxpregistrycleaner.com/0x80041321-error-win7-system.html
In case you do not find these tasks in task scheduler, I would suggest you to follow the steps below:
1. Click on Start; in the start search type cmd.
2. Right click on cmd.exe and “Run as administrator”
3.
| cd %windir%\system32\tasks\Microsoft\Windows\WindowsBackup <br><br>del AutomaticBackup <br><br>del "Windows Backup Monitor" |
|---|
4. Restart the backup again by opening “Backup and restore center” from the Control Panel”.