Using Recuva to overwrite MANY deleted files after system restore

I have just done a system restore in prep for donating a laptop. I ran Recuva in deep search and it found more than a thousand recoverable files still on the hard drive. I would like to truely erase (several overwrites) on all these files, but not by selecting one at a time, which is the only way I can see to do it right now (select one file, right click and select secure overwrite). I can select all files with Ctl A, but then the "secure overwrite" is not available (greyed out).

Anyone have any suggestions? Thanks in advance.

Joe L.

Ccleaner's wipe freespace feature is made to fit your exact situation