Hi Martin,
I am having a similar problem on my W 7 SP1 install but I have been having significant problems with it since last Patch Tuesday's KB 2838361 screwed things up for me so I haven't reported this to you. There seems to be several other Patches that people have found problems with, but I don't have them installed. Even after Recovering(I might have tried it once to many times), I logged on, on Monday morning only to find the 2nd instince of explorer.exe crashes(the first one for the taskbar etc, starts fine). I am not sure if this is causing any problems for HWiNFO or not, but I am having other sperious problems and concerns, so I am going rollback to an Image from July 03 and see how that works(this is the short story).
HWiNFO starts fine in Windows 8 RTM and Windows 8.1 PR installs for your information.
From all that I have read, this past Patch Tuesday's Patches for W 7 seems very rank indeed so I will be sitting on everything from it until the problems are worked out and outed more.
I hope this finds you well and enjoying summer,
Best Regards,
Crysta