Hi,
Yes. v10.3.9 is Panther.
I believe the issue when you visit Facebook is probably the Flash plugin and/or Java.
The system requirements for Flash are 10.4. or later, see here:
http://www.adobe.com/products/flashplayer/systemreqs/
You would need to upgrade to Tiger v 10.4.11 to meet the minimum requirements.
Try this... from the Apple Menu (top left in the PBook screen) click Software Updates. You won't be able to view Flash content on YouTube or sites that require that plugin but the Java update may help for Facebook.
If you update any system software, make sure and repair disk permissions.
Quit any open applications/programs. Launch Disk Utility. (Applications/Utilities) Select MacintoshHD in the panel on the left, select the FirstAid tab. Click: Repair Disk Permissions. When it's finished from the Menu Bar, Quit Disk Utility and restart your Mac. If you see a long list of "messages" in the permissions window, it's ok. That can be ignored. As long as you see, "Permissions Repair Complete" when it's finished... you're done. Quit Disk Utility and restart your Mac.
Carolyn 🙂