Tyan Computer GX21 - Manual (Page 46)

3.4 Replacing Motherboard Components
38 Chapter 3: Replacing Pre-Installed Components
3.4.3 Removing the Motherboard
Follow these instructions to remove the motherboard from the
chassis when all add-on components have been removed.
1. Remove the 8 screws securing the motherboard to the
chassis.
2. Remove the motherboard.