Nice and clean, easy to navigate, but:
Unless the pop-up is some kind of term of use for your site, get rid of it (pet hate of mine).
On the left descriptive text copy on the first page you have "Welcome to nitramSOFT, creator of free programs The Lock and the soon to be released Desktop HyperSpace."
Since you want people to look at your programs, I'd think about putting the program names in bold or strong tags to make them stand out and you could also make them into hyperlinks to the relevant pages of the site.
Finally, the terms of linking to your download files at the bottom of the page: you could be inviting trouble since you've just told the world how they can shut down your site. It might be unlikely to happen, but sooner or later you may well encounter some kind of idiot who reads your statement and out of pure mischief sets you up as a target by posting download links in all the wrong places.
The site looks good though. Well done you.