On a normal keyboard, it is usual for the "PrtSrn" and "sysRq" (system Request) to be together on one key. On the normal keybord, "Insert" is found as a stand alone key. Some laptop also has the Insert or "Ins" alone, but if it is incorporated with other functions in the same key, then you have to press a "function select" key in conjunction with the key. Usually, the "Insert" in the front of the key is colored, e.g. in blue. There should be another key elsewhere in the keyboard named, e.g. "Fn" also colored blue, which you have to press together with the "Insert" key so as the select "Insert" instead of "PrtSrn/SysRq". I do not have PrintKey Pro, but it seems that it takes over the "PrtSrn/SysR" function.
I do not have a Dell laptop, so I am not able to describe fully. Hope this helps.