I had the same issue as others, but with something on top.
Windows 10 notified me that Speccy wasn't compatible with W10 and that it had removed it (without my permission, annoyingly enough).
I reinstalled Speccy and it seems to work fine, but whenever it's running my keyboard will drop random letters for no reason, maybe about 1/20 times.
I tested this thoroughly with notepad, by typing something repetitive like ioioioioioioio and looking for ii or oo strings.
They only appear when Speccy is running, with great frequency. As soon as I close it my keyboard works fine again.
Until this is fixed I'll have to leave it disabled.