Automatic upgrade to WordPress 3.0 now my site is gone

I tried to upgrade to WordPress 3.0 today. I did an automatic update, told me it was successful. Then I tried to go to another page in the dashboard and it gave me an error message. I’ve seen other postings saying there were problems with plugins, but I don’t have any of the ones I’ve seen as people having errors with. It did mention the extended categories plugin in the error message, so I deleted it, but that didn’t solve it. Now when I try to go to my site, everything is completely blank.

I am a total novice with this kind of thing, so any help would be appreciated, but I really need it spelled out. A friend of mine guided me through to try to do a restore, but it is a huge file and taking hours, and I really need to get everything up and running as soon as possible.

Thanks in advance for the help!