BSOD message: Device Driver has corrupted the executive memory pool
Ran a cleaning phase (extensive, but careful) with CCleaner, and after that WFS.
I'm thinking the Wipe Free Space may have corrupted some part of the hard drive. Did abort the process because I didn't feel comfortable running it before any defrag etc
WFS should be only used if you are selling the HDD (or getting rid of it, or gifting it to someone...). When you wipe "free" space on the HDD, you basically overwrite the previously normally deleted files (files that an OS can't normally see), or in other words, you securely delete them, so that a recovery program (for example, Piriform's Recuva) cannot recover them back. Anyway, I doubt this caused the BSOD.
Try updating the drivers for the device that gave you a BSOD. Maybe that can help.
EDIT: To answer your question, maybe it is possible that CCleaner caused this, in case you deleted some temporary files that the device relied on. But in that case, the device (or its drivers are) is to be blamed, because no normal device would depend on temporary files.
If any software provides a CANCEL facility that should be safe to use, otherwise the software is defective.
If the software is terminated by using Task Manager to kill it, or shutting down the computer, results may vary ! !
I have never run WFS so I do not know what may apply to this specific situation.
p.s. Once when I ran chkdsk it only took a few minutes as it rapidly listed many things it was checking and possibly fixing. Suddenly it froze with no further actions for an hour before I tired of waiting and cancelled with the Power switch.
When I rebooted I was not happy !
I learnt to get advice when thinking of shutting down a system utility,
and that before entering that situation I need to have a Boot-CD and system restore facilities lined up and ready to go.