I think anti-virus software is a necessity.

Dear Cuffy, I welcome your help.

Thanks for the reply 4wd. What I want to do is create a system image backup of C: drive. I can easily backup to an external hard drive. When I choose my SanDisk 32 GB pen drive, I get the error message, "The drive is not a valid backup location." My C: partition occupies a mere 20 GB while the pen drive has 28 GB free space.