Memory recognition

I have a Gigabyte GA-MA78GM-US2h MB w/AMD Phenom 9750 Quad Core 2.40GHz Proc. The memory as follows: 4 GB but the software programBelarc only shows 2814 MB of installed usable memory. Why is this? I suspect this is why i am having a problem playing DVD's lately. Is some program eating my memory.I try playing a DVD movie with no other programs running that i am aware. I went started msconfig to see what programs are running on startup and disabled most of them witht he exception of essential programs to run the system. I purchased a Liteon 8x multidrive/includes Blu-ray viewing capabilites. The system is not recognizing this additional hardware as well. I downloaded a Cyberlink BD advisor and get a mesage that i a have no software players installed. I installed the Cyberlink software that came bundled with the Liteon internal player. This is about the time in began encountering my memory problems. I uninstalled the BD software, disconnected the Liteon player and reloaded my original DVD player software...worked fine 3/4 of the way through a movie and then began freezing. Any ideas out there.Cheers and beers to allI may have figured it out...I am running a 32 bit v. of windows. My processor says 64 bit ready. Can i install a 64 bit upgrade over my 32 bit v. with out doing a complete clean install? However i still have the question concerning the DVD problem. Thanks for any help provided. I have always enjoyed this forum. Have just now found time to get back in to the swing of things.

Do you have a separate video card or an on board one? If it's on board memory will be used for that lowering the amount of usable memory. About the max memory a 32 bit system shows is about 3.25 gig. The video problem may be related to your video card.
Joe

I Do not have a separate video card. I think that i see where you're headed with this...I checked out the tech manual for the MB and the MB is apparently 64 bit ready. I have a 64 bit copy of Win 7. What is the best way to go about installing this. Do i need to clean install or can i try just upgrading the current 32 bit copy? Also, do you recommend i purchase a separate video card? Thanks for your reply. Cheers and beers.

I do not like upgrade installs, A clean install is preferable and will cause less problems down the road. So go Clean!!!