I am having exactly the same issue, on Windows 7 Home Premium 64bit. I also had the same problem arise with 1.15.(?) after I had used it several times with no issue. I uninstalled it, got the latest version (126.96.36.1997), and get the same thing every time I try to run it.
I tried running debug mode (checked all boxes) and kind of the same thing happened: Speccy opened, identified the OS, but then just whirred on with no further result. After a little while my computer locked up, though it was only for a matter of 10 seconds or so, but once it 'unlocked' it ran very very sluggishly. After 5-10 minutes I shut down Speccy, and it took another few minutes after that for my PC to operate at normal speed.
It might be worth mentioning that I think this started happening after I overclocked my CPU, but I have no problems with any other applications...
I'm not sure what UAC elevated means. I tried 'run as admin': no joy. I don't know what WMI service is, or what the portable version of Speccy is.
Hopefully you guys can sort this out, I really like this program, but currently it is worse than useless to me. May as well be a 'run BSOD' application :/