Hi, JAD and JAR work on all JAVA enabled devices whilst SIS files only work on Symbian based devices, mostly Nokia devices. There are two ways to go about installation of said files. One method is to transfer these files to the device and install them by navigating and running the installers through the device's inbuilt device manager. This is the cleanest and easiest method. Another method, which assumes that your friend is using a Nokia device, judging by the query containing SIS files, is to install the applications on her PC by first installing Nokia OVI Suite [LINK
], which will associate JAR,JAD and SIS,SISX files to that application. After which, your friend can connect their device to the PC and double click on the installer file, it will prompt to install to the currently connected phone. That's it.