A weird problem with Firefox

Since yesterday Firefox has started acting quite erratically. It sometimes loads only some of a webpage, sometimes it loads nothing. On occasions, when I enter an address in the location bar and hit Enter, nothing happens. No "loading", nothing. It doesn't even open a new tab upon hitting Alt+Enter.

I've also got the "half-rendered" page, you know, it looks like it has no formatting at all.

Other times it works perfectly fine, like now, when I'm writing this post.

Everything seems to be working fine with Safari if only maybe a little bit slower than usual. Also, all other aspects of networking seem to work (IM, Torrent etc.).

What version are you using? Have you updated to 3.5 (the version just released yesterday)?

Yes, I'm using Firefox 3.5.

I had Firefox 3.0 yesterday, when the problem started, and updating to 3.5 didn't make a difference, it still persists.

I would recommend deleting Firefox's plist file, which is located in:

<your home folder name>\Library\Preferences\org.mozilla.firefox.plist

Make sure Firefox is closed when you do so.

I deleted the org.mozilla.firefox.plist file and it didn't make a difference.

Any other suggestions on how to diagnose this problem?

Hmm...I guess I would delete the plist again and un-install Firefox. Restart, and then re-download and install?

Make sure to move favorites over if you want to keep them.

I would make sure you have ALL addins disabled as well.

Disabled everything and deleted it again.

Still no change.

By uninstalling you mean "delete it from the Applications folder"?

Try creating a new user account temporarily and log into that. See if there's any difference.

I'm writing this from the temporary account, everything seems to be working albeit maybe a little bit slower, but that's probably because I don't have Ad-Block configured for this account.

So, we know it's something with your account's settings and not the Firefox install or the OS. The trick is to find out which setting that is.

I imagine it's got something to do with network settings.

I fiddled around with those, but couldn't really see anything that could have an effect regarding this problem. Most if not all things are set to be configured automatically.

Any suggestions as to what I should look into?

Stumped? 'Cause I sure am.