Windows 7 backup - recurring message after changing backup location

I backed up my Win7 Ult 64-bit pc using Windows backup to a location on my NAS ( \\NAS\Share Folder Old, say).

Then I:
- amended Windows backup to use a new location ( \\NAS\Share Folder New, say);
- ran Windows 7 backup successfully (I think) to \\NAS\Share Folder New; and
- deleted  \\NAS\Share Folder Old.

Now, whenever I start my pc, I get a message that it cannot connect to \\NAS\Share Folder Old.

No other program ever referred to \\NAS\Share Folder Old, it is not mapped to from my pc and it no longer appears (so far as I can see) anywhere in Windows Backup. 

Can anyone suggest how I prevent Windows looking for \\NAS\Share Folder Old?

Thanks,

Alex