Unknown files

[astralcc]

I have a long list of files with names like 'Img_D4 Win 32 bit drive in hope_0401p.00a' all of which have a sizes of around 2,087,023 KB which must be part of a disc backup or image but I cannot remember which program generated them. Looking in properties it states opens with 'Windows Shell Common Dll' so what is Windows Shell Common Dll or how do I invoke it.