iPhoto not responsding

When I try to go to Preferences in iPhoto, I get the spinning ball. I have to Force Quit as iPhoto is "not responding." I'm using iPhoto 9, version 8.1.2 on my 2009 Macbook with osx 10.6.8. Recently I've found that if I leave the ball spinning, it stops after about 10 minutes and I can then use Preferences. This still doesn't seem like it's working properly.

I deleted the Mobileme Gallery albums, and removed the plist and cache files as suggested on other community support. I'm also in the process of deleting some photos from my 6000+ picture library.

I would appreciate any help to fix this problem?

Also, is it correct that I cannot upgrade iPhoto if I continue to use 10.6.8? If I buy a new MacBook Pro, will the photos transfer successfully?

Thank you so much. I've spent MANY hours trying to figure this out with no success.