Backup delete

ok here it goes i had made a backup of my old laptop and when i bought my new one i restored it but instead of choosing the option where it puts all the files back where they were i chose the one that put them all im one folder (not sure why i chose it) now a few months later i need to free up some space and the old backup is 20 gigs and i need those back do when i try and delete it the window starts not responding and closes shortly.
is there any way to delete this file?

Runk disk cleanup in the System tools, choose the drive where the files are on and then select the option to remove old windows files.