Could not initialize the browser's security component

That's the message I got when moving Firefox from XP to Vista. Here is the full message I got:

Could not initialize the browser's security component. The most likely cause is problems with files in your browser's profile directory. Please check that this directory has no read/write restrictions and your hard disk is not full or close to full. It is recommended that you exit the browser and fix the problem. If you continue to use this browser session, you might see incorrect browser behavior when accessing security features.

But, let's take a step back for now. My XP computer was starting to behave strangely for some time now. I knew it was not the XP because I could not boot at all. It would hang before detecting the first hard drive when booting. Also, XP would completely freeze that I had to unplug the computer. In my case, all my data, including Firefox, are on another hard drive. Yes, I have 2 hard drives: one for XP and the other for my source code, Firefox/Thunderbird, my documents... So, before my computer decide to die or not on me, I decided to buy another computer. I then moved the second hard drive to the new computer. I did not buy the fastest computer but something faster than my current one and available in stock at the stoe. If I could, I would had waited but sometimes, you don't have a real choice. I will make a post later on. Back to my "Could not initialize the browser's security component". After some research, I could still not make Firefox work but found 4 reasons: 1. Hard Drive capacity That could not been it since I was low with less than 1 GB out of 250GB capacity. But okay, I'll bite and moved some files around. Even with 5Gb of free space, I still had the same message. So, it was not that. 2. Files permissions I'm not sharing my files but they also mentioned cert8.db must not be read-only. After verification, it was not read-only. So, it was not cert8.db. 3. Corrupted File They also mentioned cert8.db could possibly be corrupted. Having crashed a few time and had to close the computer with on/off or unplug it, it could had been the best possibility so far. I deleted cert8.db but it did not work and let Firefox recreate one for me. So, it was not file corruption. 4. New profile A new profile could become corrupted for any reason. Mine is an old profile so it was not that but the corrupted files scenario did worry me. So, I installed Thunderbird and had the same message: "Could not initialize the browser's security component" or something similar. Thunderbird is in the same main folder that my Firefox files. That's when I got a feeling it must be something about the folder itself. The solution I looked again but saw in the Security tab that \Administrator and \Users both did not have their permissions to allow Full control. Since, I moved the drive and not copy the data from the drive, it did not give me Full control on that folder. After editing the Permissions and allowing both users Full control, I was able to open Firefox and Thunderbird normally. After that, I had the same problem saving an existing text file with notepad. So, I did the same thing on my whole hard drive. Bye, Bye "Could not initialize the browser's security component" ;)