I think I have a memory problem. The Internet is extremely slow. If I try to play a short video from a text message link, it often won't play. Frequently when I try to search for a name in my contact list, the contact list crashes. If I turn off my phone and then turn it back on, the video will run and the contact list search will work. I have to turn off my phone several times a day. I have plenty of space on my SD card. How can I fix this?