2.6.2 upgrade problem, blank site

Two weeks ago I downloaded 2.6.2 and went about upgrading my blog like I normally do. Before I go on, I would like to say in advance that I searched this forum with every term I could think of, and even though I found some posts that were close to my problem, or that echoed problems I had had previously in this process. I apologize if I have missed anything pertinent.

I kept getting errors, and a previous post here in the forums said to reset the permissions (folders to 755, files to 644), which I did. After I did that, I was able to log in, write a post and save it. But when I went to view my blog, the entire page was blank. Since I was at school at the time, I didn’t have time to fiddle with it, so I left it. When I tried to login today, I got the same errors, and had to re-chmod everything because they’d been reset! If I reset the permissions everytime, I can log in and save a post, I just can’t see it, even through the preview.

I’m confused, because I don’t know what to do. Usually I have an error number to work with, but it’s just blank. Does anyone know why it’s blank, or why the permissions keep resetting themselves?

Any help would majorly be appreciated.
– fotg