What (e.g., Core i3, Core i5, Core 2 Duo) are you trying to install?
To find the correct manual, you must first identify your board's AA (Altered Assembly) number Intel Desktop Board 21 B6 E1 E2 Manual
The DZ77BH-55K is a powerful board, but even the best hardware can encounter problems. The user guides and product specification are invaluable for diagnosing issues: What (e