I have Samsung Galaxy S2. My GPS doesn't work. It just says "Waiting for location" the whole time. At first when I bought phone, I think it worked correctly, but now it doesn't. I tried: androidng.com/fix-galaxy-s-gps and similar stuff, nothing helped. How can I enabled the GPS function?

P.S. I installed a few apps for battery savings, I disabled them now, maybe it was a cause? But it still doesn't work. I could reset everything probably, but then my apps would be deleted, right?