Depends on HOW you ordered the new RAM.
The Commandment when upgrading RAM is
it must be an exact match to your motherboard.
Therefore, your motherboard's manufacturer is the last word on what you need. There is a problem with some memory specs, they can leave out very important information.
So if you order by written spec only, you could end up with RAM that will not work on your motherboard.
Reinstall your old/working RAM, then I suggest you use
4AllMemory's [Check My System] applet.
This will download a small, temporary, applet that will read your motherboard and return a WEB page showing you what you already have installed, memory slots, an a list of
compatible memory upgrades. If your motherboard is a brand-name, it will have the motherboard manufacturer's part number (like for my MSI motherboard).
Highly suggest you print the return WEB page for your records.
Of course, you need not buy from
4AllMemory, but at least you'll know what you needed and you can compare to the new memory you ordered. In fact, AFTER getting the correct memory spec, search
4AllMemory for the new memory you ordered and see if it matches.