What OS are you using? Are you using other security software?. If you are running Vista or 7, try running the install as administrator. If you are running other security software, disable it when installing CIS. You also may want to check Windows event viewer for any errors.
On my main computer (french Win XP SP3 X32), when I start the installer (tried 3.14, 3.13, and a few older versions), I get directly the empty window you can see on the screenshot below (the window asking the language is skipped), the next button does nothing.
ZoneAlarm 7 free is installed on this computer, but I’ve installed CIS on several others computers and virtualboxes with the same OS, some also with ZoneAlarm running, without any problem.
[EDIT] I just saw there was also a help forum where someone has the same problem : https://forums.comodo.com/empty-t48558.0.html
A moderator could perhaps move this topic in the helpsection, or merge it with the one mentioned above.
I was too lazy to uninstall (in fact, to reinstall after uninstalling) ZA until now because it doesn’t allow to export settings (and because Comodo works perfect on other computers with ZA). I made this effort today (and removed everything I could with ccleaner and regseeker, cpes_clean.exe doesn’t work on my system, the process closes after one second) but this has changed nothing.
I don’t know what initialization is done when CIS installer is run, but the fact that the window asking the language is skipped and the main installer windows is shown without text make me think about a potential problem with OS language settings. I’ve checked that the configuration on my main computer is the same that the one of my other computers.
Now I made the effort to remove ZA, I wont reinstall it, so I’ve installed PC Tools Firewall for now, but on a first touch I really prefer the look&feel of Comodo (more clear, more advanced) and I like Defence+.
If this problem is not corrected, I’ll have to wait my next OS installation to try again, and I’ve no installation planned (too many work).