Q1. I take it you are only talking about the cleaner program and not the registry cleaner (issues) part?
A1. Yes, just the cleaner part.
Q2. There is no way CCleaner can be invasive on your machine as it is basically removing temp files etc from the machine.
A2. Obviously a false/incorrect statement as this is the second time an OS load is required on the laptop after running CCleaner.
Q3. Do you have to enter any info on startup for your encryption program? Could any of this info be stored in a temp area?
A3. No, the encryption login in integrated into Windows login and work systems' logins. I do not know where the programs loads anything.
Q4. Could your encryption program see the cleaning as a threat perhaps?
A4. Unknown.
Q5. If you can get that error message number it could be useful.
A5. OK, The IExplorer issue provides an error message. But the failed boot just freezes, no error messages.
Q6. Also try a test of booting up in safe mode and see if you have a problem then.
A6. Laptop will not fully boot in SAFE mode either, seems to hang and no go further.
Q7. I take it you have done all virus/malware checks and have no reason to think there may be a problem in that area.
A7. Symantec SAV10 constantly monitors the laptop. And when I run other utilities such as Spybot or AVG, it finds no issues.