Se7520bd2 - I installed 4 GB of ram (2 sticks) I added later another two ram chips the same mobel. The M/B is not recognizing the 2nd set? My Emial is [email protected]

Check ur Motherboard config....it may not be made to have more than what it's capable of....though u may have 10 RAM slots the total of RAMs put together(all RAM cards) should not exceed than the total that can be handled by the MB....check ur MB manual or the mfg for the max total RAM that it can handle...also if it's DDR or SDR...then all shoudl be the same DDR or SDR any combination will not work...the best is to use a RAM checker software(google it)
u can also use the MS Office 2007 tools to check ur system config including the RAMs

1) unless your operating system is 64 bit, your computer can only use 3 GB RAM maximum, so 4GB is a waste of time.

If you already had two identical sticks of RAM, chances are your BIOS is setup to recognise twin channel RAM is it has larger bandwidth so it is quicker. To use two channels your RAM must be identical in both channels, clearly if 3GB is the maximum you have a lopsided config and you have to swap the BIOS to single channel RAM.

Of course if you have already checked the BIOS rather than windows, and it still only sees 2GB RAM, the problem is a different one.......