How to install Service Pack 3 for SharePoint 2007 Server?
1. Download and Install Service Pack 3 for Windows SharePoint Services 2007 (KB2526305), 64-Bit Edition
If you have multiple front end SharePoint servers, you need run Service Pack 3 in all servers
2. Download SharePoint 2007 SP3 for 64bit and install in your SharePoint 2007 server
Once the update is installed, you will get SharePoint product and technologies configuration wizard. Run the configuration
Wizard to install SP3 udpates
You must run setup to install new binary files for every server in your server farm. If you have
multiple servers in your server farm, run setup and the configuration wizard on the other servers now,
and then return to this server and click OK to continue.
4. Restart your server