Dell Precision T7400 (Late 2007) - Manual (Page 188)

188 Adding and Replacing Parts
2 Remove the computer cover (see "Removing the Computer Cover" on
page 141).
3 Loosen the captive thumbscrews that secure the memory shroud and lift it
away from the computer.
CAUTION: Fully-buffered memory modules may become very hot during normal
operation. Ensure that memory modules have had sufficient time to cool before you
touch them.
4 Disconnect the power cables from memory riser cards 1 and 2.
1 memory shroud 2 thumbscrews (2)
1 2