PSPad works under Win64 without any problem. 
I didn't receive any report that installer 4.6.1 doesn't work under any Windows

Download ZIP (portable version)
Unpack it anywhere you need and run.
If you untack it into program files folder, run PSPad as administrator then,
open program settings / System integration and check [x]Multiuser environment

PSPad freeware editor

Odpovedet emailem