Suggestions:
1. Run Activity Monitor, choose "All Processes" and sort the list by %CPU. Is anything eating up your CPU? Is it VShieldCheck (Virex)? If so, uninstall Virex according to the directions in the Remove Virex thread.
2. Wait a little while (45 mins?) for Spotlight. The initial indexing can take more time than this, but allow a few minutes of idle time for indexing.
3. Search the forum for Safari-related posts in the last week and see what else has been mentioned.