Opening up the PC, there should be motherboard make/model written on the motherboard, usually in white lettering somewhere around the middle area of the motherboard.
Memory modules should have labeling/marking on them which indicates make and model/part number.
If there are problems identifying the parts, download and run
HWiNFO32/64. Select Summary only check box and then click Run button. Motherboard details are near bottom left of display. And memory details are shown at middle right of display and directly under "Memory Modules" text as manufacturer name and part number.