Safari closes upon opening

Please help, As soon as I open Safari it closes. I have little mac troubleshooting knowledge. I have installed all knew updates. I currently using Version 4.0.3 (5531.9) of safari. Mac OS x is version 10.5.8
Does anyone have a hint of idea what i should try. Thanks

If Firefox or any other browser works, trash Safari and go on over to Apple and download a nice new fresh version, double click and install in Applications and let's know how you go?

Apple - Safari - Download Safari - Download the world’s fastest and most innovative browser for Mac and PC

The Leopard version should be the default, but double check.

Sounds like a corrupt app file or even a bad HDD.