Because it works for any one person with their almost perfectly unique combination of hardware, BIOS versions, driver versions, and cohabitating other installed software, doesn't mean it works for everyone. That should be obvious, but reading some of these posts I truly wonder... Blanket statements of "it works fine for me, so you have a virus/antivirus/driver problem" are a poor substitute for useful accurate information. CD-based install doesn't work for crap on my 64-bit Vista HP machine... drivers, OS, and BIOS are up to date. Spins the CD for a second, then nothing. Nothing posted here makes any difference. I can read all the files on the CD, I've copied and tried from the hard disk, I've run as admin, I"ve put in appropriate DEP exceptions, etc. The only approach that worked for me was copying the installed directory from my old PC. Works fine, no issues, runs great. I doubt I would have ever found a solution otherwise. It's a shame EA doesn't take supporting its PC users seriously any more... not only can you not find any information on this issue on their site (other than a page of vague, generic, hand-wavy stuff that is almost no help), but they'll still happily sell you a SC4 CD without discussing the compatibility requirements. It sure was a different company back when I worked there.