How to continue using a VOCALOID trial version (or demo) after it expires?

It's really simple.
Short explanation:
Just have to clear the registry information, and reinstall.

Long explanation:
Assuming that you already have installed any trial (eg MEIKO POWER V3), and have spent the 14 days (or whatever) and now is expired:

Run the Registry Editor: 

• Windows 7: Start> and type "regedit" 
• Or the Windows key (the flag) and R and type "regedit" 

Find HKEY_LOCAL_MACHINE\SOFTWARE\VOCALOID3

::In 64Bits machines: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\VOCALOID3

And remove the entry VOCALOID3 and if you want, VOCALOID3TINY.

And that's it. You can re-install your trial/demo!

You don't have demos? 

Here is a list!