Even apps on your SD card take up memory in your phone (some more than others). If you go into the applications menu located in Android settinga & choose manage applications, you will see a list of apps that on the phone. When you click on one it lists memory usage (total, application, data, & cache). If the app shows on the SD card, anything listed under "Data" & "Cache" is still taking up space on the phones internal memory. Some simple ways to deal with this are: 1) look at your bigger apps & find out which ones leave too much "data" on the phone & delete them; 2) download a program to manage you're memory (such as ZD Box) which can easily & quickly clear you're cache. It will also be an easy way to do step 1. If her phone is rooted there are other good options.