Not yet, I've been putting that off, because the login loop stayed after last time I reinstalled. see this timeline:
- Before I changed my short name, running 10.7.0, I backed up and all was fine.
- After short name change but before 10.7.1, all was fine.
- After 10.7.1, login loop problem
- Reinstalled and ran Migration Assistant, returned to backup of 10.7.0, was fine after that.
- Updated to 10.7.1, startup hangs; later, login loop problem returns unexpectedly
Therefore, I'm thinking that rather than reinstalling and migrating, I'll fashion my own Archive and Install - have a folder containing previous system on a completely fresh Lion installation, because then I can be fairly sure I won't have these problems again.
However, I'd much prefer to run a few terminal commands in Recovery HD than go through all that effort.
Back up with TM, boot from the recovery partition, erase the main boot volume, reinstall Lion, then restore your data from TM in Setup Assistant. If that doesn't work, you have to consider a hardware fault.
Well, thanks for your help.
I've now logged in via the Other User: ">console" trick, now copying everything that wasn't backed yet up to an external HDD I've mounted, doing a clean Lion install, copying files back.