It is likely that the program found so many files that your system's memory and virtual storage (pagefile.sys) are overtaxed. If you wait and wait, the program will probably eventually finish marking all the lines as selected.
You can change the settings to look for a smaller set of files. For example,
Also, none of the options in the other tabs should be checked. Otherwise, the program will be doing multiple things at the same time.
Be sure you heed the program's warnings. It is not safe to delete files just because they are on the list. You have to know what you are doing.
If you do delete anything, make sure you say Yes to the backup question!
