When IIS is running is ‘IIS 5 compatibility mode’, MOSS have lots of issues like:
1. Corrupted Word Documents when open from a document library
2. No Application Pools are visible in IIS 6
3. SharePoint Central Administration – An unexpected error has occurred.
4. ASPNET user cannot access SharePoint databases.
To fix this, from IIS > WebSites > Properties > Service > uncheck IIS 5.0 Compatibility mode