Welcome to Apple Support Communities.
First, use the Safari menu and Empty Cache, forcing web pages to reload entirely.
If that doesn't help, check to see which version of Safari is installed now.
It's quite likely you're now on Safari 5.0.5 after the reinstall of OS X 10.6.8.
For some reason, Software Update does not offer to install the latest version.
The latest version of Safari for OS X 10.6.8 is 5.1.7, available to download from this non-Apple link at macupdate.com, a reliable vendor of Mac software. Click on 'Download Older Release' to get the correct version:
http://www.macupdate.com/app/mac/15675/apple-safari
I responded to a similar thread earlier today, although that person was having problems specifically with Flash content:
https://discussions.apple.com/thread/4257316?answerId=19445640022#19445640022