Hey Andres,
How annoying on this last day of the year (depending on your location), sorry to hear about your trouble.
Just as a side comment, it is always good to include your technical specs in posts related to performance.
My suggestions would be:
1) How full and how fast are your drives running?
There used to be a rule of thumb that your drives should be 25% empty when working with video, as this makes them run faster. If your drives are full, start by creating more space.
And, just in recent years, I’ve been given USB-2 Hard-Drives to edit HD multicam from. One project was FCPX, and one was PPro – both had the same “problem”.
2) Trash your preferences and renders, and see if that unfreezes the sytem.
3) Setup a new PPro project (v2), and import in the last sequence.
Yes, you may have to import all of your other footage + re-render all files.
4) Power down the computer, take a half-hour break, then turn it back on.
Sounds crazy, but often works.
Hope that this helps you.
HAPPY NEW YEAR!
Atb
Mads