It is most likely it popped off sometime after it was in operation.  With heating and cooling comes contraction, and most likely broke loose after hours and days of use.   To fix the issue properly requires replacing the whole motherboard, since those parts are not available individually and only come mounted on the motherboad.   Regards,
Has anyone else ran into this problem? I recently replaced our server with a new one so I decided to take a look inside our old Poweredge 2900. I removed the side panel and low and behold one of the heat sinks from one of the chips was just laying there. One of the little white hold down loops that the heat sink attaches to was in the board and the other one no where to be found??? Also, on the lower half of the same board on another heat sink (still glued onto the board) had its wire hold down (on the sides of the heat sink) popped up. Meaning they weren't attached to any white hold down loops (the right loop was on the right hold down wire but had slid down, off the board, to the heat sink). Just wondered if this has been a problem, or, since I hadn't looked inside when I originally set it up if it may have come from Dell that way???
Heat Sinks fell off?