The Configuration Manager Support Team blog posted a great article on ConfigMgr 2007 SP2 install failures.
This document was created to help in troubleshooting Configuration Manager Service Pack 2 (SP2) install failures. This document is not entirely specific to Service Pack 2 and can apply to Service Pack 1 installs, upgrades from SMS 2003 to SCCM, and future service pack or Configuration Manager versions that rely on .mof file compilations, SQL SPNS, provider DLLs, etc.
Section 1 Pre-Upgrade Best Practices
Section 2 General Troubleshooting
Section 3 List of Known Issues and Solutions
If you want, just take a look and learn from it.
Read more at source.