Motherboard Swaps in Old-Skool Dell Cases

[PGHammer]

I know of at least two DELL Dimension 2400 motherboards that are about to croak - the motherboards are, in fact, the only issue. (The *newer* of the two is eight years old - both are based on the Pentium 4 (Northwood-B) S478 CPU.) Ideally, I'd prefer to do a straight motherboard replacement, given the cheap prices of LGA1155 (Sandy Bridge) barebones. Both are currently running XP32 (XP Professional); however, that is entirely due to their low RAM loadouts. However, how do I re-use the front-panel (power switch, etc.) connection between motherboard and case?