Dell Precision M60 - Manual (Page 95)

9. Ground yourself and install the new memory module:
a. Align the notch in the module edge connector with the tab in the connector slot.
b. Slide the module firmly into the slot at a 45-degree angle, and rotate the module down until it clicks into place. If you do not feel the click, remove
the module and reinstall it.
10. Replace the cover.
1 securing clips (2 per
connector)
2 memory module
NOTICE: If you need to install memory modules in two connectors, install a memory module in the connector labeled "DIMM A" before you install a
module in the connector labeled "DIMM B." Insert memory modules at a 45-degree angle to avoid damaging the connector.
NOTE: If the memory module is not installed properly, the computer may not boot properly. No error message indicates this failure.
NOTICE: If the cover is difficult to close, remove the module and reinstall it. Forcing the cover to close may damage your computer.