Long story short, I'm selling my computer to my girlfriend and buying a new one, and since the Sims 3 is her favourite game, she brought over her disks (base Sims 3, Medieval and 5 expansions) to try it out, and we hit a roadblock where the base game just won't install. The rig I've got vastly exceeds what is required to play the game, but every time we try to load it, it gets to about half way done before crapping out, specifically this most recent time "Data error (cyclic redundancy check).
Googling has shown us that while Sims 3 is not officially supported for Windows 7, it should run on it, which indicates to me that it should bloody install at the very least. We've found recommendations to eliminate the EA Download Manager (done, I had used it previously for Dragon Age: Origins and Mass Effect 1 & 2 DLC), I've never had a Sims game on my PC so the issues with reinstalling shouldn't be affecting us, and I'm sitting on about 500 gigs of open space so it's not like this should be challenging my system's resources. Trying to copy the disk to the hard drive and install from there has the system apparently choke on some of the large .package files, but I'm surprised a mere gig or two file would cripple a system.
So it's not an issue with "let me Google that for you", so much as I'm looking for suggestions, tips or tricks from anyone who might've hit this problem and overcome it. She has all the original disks with codes on the packaging, so it's not a matter of piracy or making a mismatch of versions work.