Several files unaccessible by me. Is this a virus?

[system]

Using Windows 7 home premium.
I found that I could not access some files on my computer which were copied from my laptop as a backup of the laptop. If I try to copy the backup folder, the system copies most of the files, but stops with an “access denied” message. On investigation, of some of these files, I find that if I try to right-click to look at properties, I am told “I don’t have permission…”. But I can continue to try to find out who the owner of the file , it shows “Unable to display current owner”. I have never seen this before.
It has made my backups untrustworthy.
What could have caused several files to become"infected" in this way?

[Pondus]

What could have caused several files to become"infected" in this way?

this is no indication of infection as far as i know...

[system]

@Bob.M post:1

Using Windows 7 home premium.
I found that I could not access some files on my computer which were copied from my laptop as a backup of the laptop. If I try to copy the backup folder, the system copies most of the files, but stops with an “access denied” message. On investigation, of some of these files, I find that if I try to right-click to look at properties, I am told “I don’t have permission…”. But I can continue to try to find out who the owner of the file , it shows “Unable to display current owner”. I have never seen this before.
It has made my backups untrustworthy.
What could have caused several files to become"infected" in this way?

Well it’s not a sign of infection. I too experienced same issue, copy all files on other partition/external hard drive. And format the partition this is the only way I fix this annoying issue. If you set to have permission from the properties meniu, believe me is a waste of time, because next time when you will reinstall the windows you will face same problem again and again. The only way I manage to solve this issue is by formatting the partition.
Regards RealNature,