Q: computer locks up

No worries, I shall be here waiting for your report.

After rebuilding the spotlight index, trigger a backup. Your time machine backups are automaticly performed hourly as long as the drive is connected but consider going to the time machine icon at the top and choosing backup now. Check the performance of your backup. I mean the speed varies of course, USB/Firewire, if a lot of data has to be backed up, if the previous backup was interrupted but you should get a feel for it after the fact.