I have a serious problem with my hardrive memory. I use to have 40gb of 70gb used on my hardrive. Just recently I have begun to receive messages stating that my memory is low. When I checked on it there were 4.4mb of 70gb free. I have no idea where the memory went. I cleared 10 gb off my hardrive and onto an external drive. A week later i was back down to 4mb. I cleared another 2gb which was also chewed up. I have no idea what is going on and I need major help. Doesn't anybody have a clue what is happening and a way to fix it?