If, for example, I have many files with an extension that I want to delete, let's say .dcm, is there a way to tell Explorer to do so without my have to select each and every file and then hitting DEL?
If there is various extensions in the same place hold the cntrl key down while you select the files and then delete them all at one time.
If you have a directory with mostly the same extensions you can select the first one and then press the shift key. Then select the last one and all of the ones in between will be selected. Then delete them. Be careful not to get one in there that you dont want.
You can also use search to find them and one of the above methods to delete them if you have a lot of them.
Using the search there is also a select all option in the edit menu to select all of the files at one time and then they can be deleted.
The funny thing is it recognizes just about any extension except .dcm which is created by a backup program I used and seems to populate my computer with hundreds of extra files