How do I upgrade RAM in Latitude E5400?

i would have bought another dell memory module as the one that originally came with your dell, and you would probably would have had no problems......its possible that the memory module you bought is not compatible with the dell module you have installed. ,,,possible timing differences,,,etc.....

Welcome to the forums Millie :emotion-5:

Whilst I agree to a point with what Ron says above, most RAM modules *should* work with any other of the same type/speed - i.e. your 2GB PC2 6400 SODIMM should work with the 2GB PC/PC2-6400 pre-installed by Dell?

But the only way to ensure compatibility, is to use two modules which are exactly the same, preferably bought as a pack - i.e. 4GB (2x 2GB) dual channel PC2-6400.

So either get another stick of the RAM you've bought, or... if you can afford it, but a new 4GB pack.

Unfortunately however, you can't necessarily buy whatever RAM you want, because there's no guarantee it will work in your laptop!

But since the RAM you bought is recognised/does work in your laptop, it would be fairly safe to assume another 2GB stick of the same RAM would also work :emotion-55:

Alternatively... Crucial guarantee their RAM to be compatible with your Dell system. 

Plus of course their RAM carries a lifetime warranty, and their support is reported to be first class, should you ever need to use it.

You can use either their 'System Scan Tool' - which will do exactly as it says on the tin, and scan your system to see what RAM is in it just now, or use their 'Memory Advisor Tool', and select your specific laptop ;)

I've actually input the details for you, and you'll find the RAM they suggest for your Latitude 5400 here.

That's the Crucial UK site though.  If you're in the US, this is the page you need :emotion-21:

:^/ I've checked, and your model will support up to 4GB of RAM, but in my experience Dell hardware is fussy and requires the RAM modules to match.  So, while your new module will work, the two don't play together nicely so only one is recognized.

i failed to add in my thread,,,that some brands would probablly work with your dell memory,,,crucial would be my first choice, along with some of the main brands-corsiar-kingston-.......but some computers work better with one brand, not so with others.

I wish I had sought advice before making my first purchase. I played it safe this time, I hope, and ordered 4gb Crucial per their recommendations for compatibility. Looking forward to trying that when it arrives. Thanks for all the advice! Millie