Something went pretty wrong there if you can't even run the system file checker...
Take another try at this.
From your Windows' control panel, use the installed programs list to delete the VC++ AND .NET versions you already have, if any, starting by the most recent.
Once you're done, reboot, then look up for and download the latest revisions of those two libraries, then install them and reboot again.
Try running the game and, only if it doesn't work, install the 2005 package.
Otherwise, at this point, I actually suggest you start from scratch. Backup anything you can't afford to lose and try running a system repair through the OS disc. If it doesn't work, reinstall it.
Not being able to run the SFC isn't a good sign...