error message when trying to back up

I have been trying to back up my hard drive using Vista's built-in back up.
It has worked before but now i keep getting this message....

The backup did not complete successfully.
An error occurred. The following information might help you resolve the
error:
Access is denied. (0x80070005)
Backup time: 3/31/2008 8:13pm

Backup Location: The backup disk cannot be found.

i am backing it up to an external hard drive...i dont know why it says
cannot find hard drive...the drive showes up in my computer and in the
settings for backup

any help????

Re: error message when trying to back up

"Dom" wrote in message
news:A43F70EF-B6C8-4609-A3E3-BBFD5F7B8F86@microsoft.com...
>I have been trying to back up my hard drive using Vista's built-in back up.
> It has worked before but now i keep getting this message....
>
> The backup did not complete successfully.
> An error occurred. The following information might help you resolve the
> error:
> Access is denied. (0x80070005)
> Backup time: 3/31/2008 8:13pm
>
> Backup Location: The backup disk cannot be found.
>
> i am backing it up to an external hard drive...i dont know why it says
> cannot find hard drive...the drive showes up in my computer and in the
> settings for backup
>
> any help????
>

As this is a .NET programming group, consider posting in a Vista group.

To find the group you need:

As you appear to be using a web interface...

http://www.microsoft.com/communities/newsgroups/en-us/defaul t.aspx?guid=1080912A-26C5-7040-AFDD-2224A4FEB3EA

Select your language from the Tree View on the left, then scroll down to
Windows. In the Windows category, open the category for Windows Vista.
There, select an appropriate group.