Dell XPS 730 (Late 2008) - Manual (Page 28)

26 Replacing Memory Module(s)
If you insert the module correctly, the securing clips snap into the cutouts
at each end of the module.
9 Replace the computer cover (see "Replacing the Computer Cover" on
page 17).
10 Connect your computer and devices to electrical outlets, and then turn
them on.
If the message appears stating that memory size has changed, press <F1>
to continue.
11 Log on to your computer.
12 Right-click the My Computer icon on your Microsoft
® Windows ®
desktop and click Properties.
13 Click the General tab.
14 To verify that the memory is installed correctly, check the amount of
memory (RAM) listed.