CCleaner 412 portable starts a process but never displays a screen under XP x32 SP3.
Runs fine for me.
Probably check your antivirus logs to make sure that isn't the cause. Also if you were extracting over a previous version perhaps extract it into a brand new folder.
Thanks. It must have been some temporary system glitch. After a reboot and another extract, everything works normally as it usually does - even though I'd tried it several times last night.