WinDVD Region Hack
Please note, the following instructions only work if your Blu-ray drive is a type that does not have hardware based region coding.
Certain Blu-ray enabled PCs and laptops come with WinDVD as the Blu-ray software player. For example, Sony Vaio laptop computers come with WinDVD BD, although it is not commercially available as a separate software package (as far as I know). Unlike DVDs, Blu-ray region settings for computer are apparently stored in software, not in hardware. WinDVD BD also has a region counter system for setting regions, meaning you get to change the region code 5 times before you are locked from making any more changes. Because things are done in software, it is easy to be able to delete the file that holds the region counter, and thus, reset the counter. However, WinDVD BD makes it slightly trickier because a system driver runs in the background locking the file in question, and thus, it won't allow you to simply delete it like a normal file. You could, of course, boot into safe mode or another operating system installed that can access the relevant hard-disk partition, and then delete the file normally. The method listed below will allow you to delete the file without having to do any of these things.
First, we need a way to disable the system driver in question. There are many ways you can do it, but this is a way that I learned by reading article (specifically, one of the comments in this article). I'm not sure where this method originated from, but a quick Google Search found this post on the Inmatrix forum.
Anyway, download and install the free Autoruns software from this page. Open up the ZIP file extract the files into a folder on your computer. Go to that folder and run "autoruns.exe". When the program starts, go to the "Drivers" tab and locate the driver "regi" or "regi.sys". Uncheck the checkbox next to it (don't delete the item) and close Autoruns. Restart Windows.
When Windows finishes restarting, go to your Windows's "System32" directory (for example, "c:\Windows\System32", or you can use the Windows Run function and type in "%WinDir%\System32" to open up this directory). Find the file "ivireg.ivr" and delete it (make a backup, if you wish).
Run Autoruns again and go to the "Drivers" tab. This time, re-enable "regi.sys" (check the checkbox next to it) and close Autoruns. Restart Windows again. When you next run WinDVD BD, it will recreate the now missing "ivireg.ivr" and it will use the default region data, which gives you 5 more times to change the counter. Hooray!