ok i have 3 gigs of ram but have a mother broad has 4 slots for ram ...can you go over 4 gigs with architecture of the mother broad may limit the ram use or is it o/s in the picture ? or both ?  

A 32 bit OS can only address 4GB - that includes RAM and everything else on the computer that requires an address, so the amount of RAM it can use is closer to 3 gigs. To use more you need to install a 64 bit OS.

 

To find out what the limit for you motherboard is, google it. If you can't ID the board, A program like HWiNFO32 (or HWiNFO64, for 64 bit) can tell you.

i am using 64 bit win 7 but any trouble with architecture of the mother broad a trouble ???

Need to know the make and model, and go the the manufacturer's website to find out. An easier way would be to go to crucial.com and run their free Memory Adviser tool, which scans your system and recommends memory upgrades. You don't have to buy from them - you can get better deals elsewhere - but it identifies your board and tells you what it can use.