I assume that "same problem" refers to another thread within the forum, but since you started a new one rather than replying, we don't know what that one was. No matter.
Since you replaced the destination backup drive, you will need to reset your backup plan and start a new full backup.
Open OneCare
Click Change Settings
backup tab
Click Configure Backup
Click change settings in the lower left
Make sure that the first screen for Centralized Backup has "No Centralized backup" selected
Click your PC on the left.
Uncheck the selection for "Turn on backup for this PC."
Click Next and save the revised plan.
Go back to the backup tab, configure backup and click Change Settings in the lower left once again.
Select your PC and click.
Click Turn on backup
Select the change location link and select the drive you want to use for backup
Modify the schedule as desired for "When"
Select the file types as desired for "What"
Click next and save the revised plan with the new selection.
If that still doesn't solve it, make sure that you didn't install any software provided with the new drive for backup that may be bocking OneCare from using it. And, if the problem persists, please contact support.
How to reach support (FAQ) - http://forums.microsoft.com/WindowsOneCare/ShowPost.aspx?PostID=2421771&SiteID=2
-steve
