From what you said earlier, it sounds like you've got the CC in the right place and you get the pop-up listing your CC, so the game appears to see that it is there. So here's something for you to try to make sure the game is really seeing it.
Start a new game using the New Game button on the Main Menu (with all your CC installed) and after you go to CAS to make the required sim, check to see if your CAS CC is there. Then finish the sim and place him/her on a lot, then while on the lot, go to build mode to see if your build CC is there. If it is, then the game is recognizing that the CC it there. If not, then something else may be going on and a repair may be in order. I know you just installed the game but sometimes if there is any type of hiccup during the download, a file can get corrupted so a repair can fix that.
One thing you could try if it is not showing up is to delete the localthumbcache file to make the game create a new one the next time you start with CC in the mods folder and the appropirate Gameplay options checked to enable it. And then check both CAS and Build again to see if it shows up.
Another thing you can try is go to Game Options and make sure the box is checked to enable CC and script mods. If it is checked, uncheck it, hit the Apply button to save the change, then check the boxes again and Apply them again and then exit the game and restart.
Now if your game is seeing the CC after all that, then that means the problem is with the save. And as @Bluebellflora said, you just may have to manually replace everything that went missing by redressing your sims and redecorating your lots.
Hope this helps.
Thank you so much but I was able to get it fixed, I think I just messed something up when I downloaded my old cc on my new computer. Thank you tho!
