I had a small stint of that once. I removed all plugins and deleted all the cached stuff and it started behaving again. Kinda the nuclear option since I wasn't discriminate about what I deleted.
I use the issued version of Safari, on my iMac, 10.7.2 Lion operating system and it works great no problems so far except when I reset safari and it drops all my log in cookies.
I had a small stint of that once. I removed all plugins and deleted all the cached stuff and it started behaving again. Kinda the nuclear option since I wasn't discriminate about what I deleted.