I've been using a Lumia 620 for the last 2 years. Now my phone is getting slower and slower. I have moved all my data to the SD card, but it is still showing only 500MB out of 8 GB. When try to remove data by accessing the folders it shows nothing in all the folders. I am confused now how I can make more space in my phone. See below screen shot from my "Storage Check" in Settings.