Build a PC BIOS shows 640k base memory and 126m extended memory

My windows xp 64 bit runs super slow after windows loading sign and it takes me 2 hrs to open up the desktop and transfer 6 images. I use 2 RAM's of 2gb (kingston DDR2). When I opened up BIOS, it showed 640k as base memory and 126m as extended memory.
There are no details under the computer title if I try to check the properties of computer or maybe it is just taking too much time to display. the desktop is fine, my computer still works but takes hours to do a simple task. it all started all of a sudden. Also I would like to know if 'unganged mode' is fine as it is displayed when the system boots. I tried to check another different RAM on the computer, but still no change, so I am confused regarding the problem.