ok so finally I got to try out windows 8, more importantly if FRESH does work on a brand new 2T HDD.
1) S$17.99 upgrade version. Brand new HDD.
2) unplugged all my HDD inc my w7 HDD from my system.
3) performed FRESH install, left w8 installation to format my virgin HDD.
4) everything loaded seems ok EXCEPT keys entered not activated (re-entry did nothing). Prompted for a diff set of key cos no traces of previous Win detected during setup process.
5) followed instructions from website to use the REGISTRY method to have keys activated
6) REGISTRY method works like a charm !' Keys activated upon restart w/o need to enter them again at any time since.
Conclusion : if your keys cannot be activated, no need bother installing trial version of w7 XP etc, just follow these instructions instead :
"Open regedit by pressing Windows-q, entering regedit and selecting the result from the list of hits.
Navigate to HKEY_LOCAL_MACHINE/Software/Microsoft/Windows/CurrentVersion/Setup/OOBE/
Change MediaBootInstall from 1 to 0
Go back to the start screen and enter cmd there.
Right-click Command Prompt and select to run it as administrator.
Type slmgr /rearm on the command line and hit enter.
Reboot Windows now.
Run the activation utility afterwards, enter your product key to activate Windows."
Thanks TS for a most helpful and insightful thread