Hi there! the above poster pretty much told you what the story is. Basically in a nutshell, sims 2 is an older game for older computers, so in order to fix the graphic problem (which is pretty much having one screen size plus texture memory), i used the tool the graphic rules maker, which pretty much tells the game your graphic card. To install it on Ultimate Collection, go to ultimate collection that is stored on your computer. If you do it by the discs, what helps me is using the graphic rules maker after installing every single ep/sp. also make sure you alter your texture memory to a near match of your texture memory for your graphics card.
i have used either or method- but basically you can only use one either origin or discs. i still use my discs for the sims 2.