I would first uninstall FCPX and M5. Then update SL – if your profile is correct – to the latest version. install FCS from the disks; run all of the updates through Software Update until there are no more. Repair permissions. Download FCPX and M5. (Be aware that if you intend to send clips from FCP7 to Motion, you will need to install M4, because there is no inter-operability with FCP7 and M5.)
Here is Apple's best practices document.