Hi again Leooel. I have another suggestion
I played with this option using Windows 7 Pro 64.
(I am assuming you have completed an install properly, but PDCU5 doesn't start up beyond the splash screen).
(1) Make sure you are logged onto Windows with an account with admin privileges;
(2) Open up Windows Explorer (or whatever it is called in Win8);
(3) Navigate to the folder C:\Program Files\PENTAX\Digital Camera Utility 5;
(4) In that folder there should be 5 or 6 files. One of the files should be called: PUTLL5.dat, which is about 12kb. Rename that file to PUTLL5.dat.BAK. (Windows may raise all sorts of objections to doing so, since you are working in a program file folder, but as an Admin you should be able to perform this operation).
(5) Now attempt to start PDCU5, either from the start menu or by just double-clicking on 'Digital Camera Utility 5.exe' in the current Windows explorer folder. PDCU5 should start, but only show the splash-screen, then fail.
(6) Now start up Notepad (still while running as an Admin user) and create a file in the
C:\Program Files\PENTAX\Digital Camera Utility 5 folder called PUTLL5.dat. Add some garbage words into the file and save it, making sure that you are saving it as 'PUTLL5.dat', not 'PUTLL5.dat.txt'.
(7) Now attempt to start PDCU5, either from the start menu or by just double-clicking on 'Digital Camera Utility 5.exe' in the current Windows explorer folder. PDCU5 should start.
In my case, on Windows 7, what this process did at step (5) was initially clear many of my PDCU 5 program settings (for home folder etc). When I created a dummy PUTLL5.dat file at step (6) and started PDCU5 again, the program ran fine and let me start work straight away, and from that point program options were saved into the registry as normal.
So this process seemed to reset some of the startup parameters of PDCU5. Maybe that is what is blocking the startup of PDCU5 for you. Maybe. Perhaps. Could be.