This is an update.
After wasting a couple of days with about everyone in the Vidéotron customer service, technical support and a visit from one one of their tech, I finally decided to take a chance and replace the hard disk.
I opted for a 500GB Western Digital WD5000AAKB and for the drive and Torx tool, I ended up spending about 135$. But I still plan on using the WD warranty on the original WD3200AAJB, it was manufactured a couple of week before the box, July 2008. I still have to research how this works.
If you want to know how this can be done, there is a lot of good information here:
SA8000/8300HD - Internal Hard Disk Upgrade Works (Cloning too)
comes with pictures and everything.