I previously posted in August 2012 at (now closed)
...] about Firefox suddenly no longer working.
I surmised at the time it may have been a hardware problem but noted that it had previouls worked. We have installed and reinstalled Flash, I have roamed ixquick using (obviously) the wrong keywords.
I have only just managed to get the machine for analysis. I reinstalled a copy of Mint on a new drive (the old one had unlinked segments and one commentator said he'd repaired a disk and Flash had then worked); Flash still failed. (Also, the new disk I initially tried, a SATA one, failed to register but that may have been my incompetence. I finally installed an old 83Gb IDE drive.)
After searching around, comparing the machine with a newer one, I found a reference on an adobe forum with MANY people complaining that Adobe had now compiled their code to only work with SSE2, dropping the previous option of SSE (these are command subsets on the processor). There were some very angry people posting there, especially people with desktops and laptops only a few years old. Checking the SSE2 wiki confirmed approximate dates, processors etc.
Adobe forum at: [bugbase.adobe.com
The Flash failure on my brother's machine was a sudden thing and, it transpires, must have followed an update of Flash which installed a version that no longer worked with Intel prior to about 2001 or AMD pre-2004. This machine uses an AMD processor and was built about 2001; it is used by my brother to familiarise himself with linux. Flash is the ONLY thing that has so far failed to work for him.
So: SOLVED but no real solution in this case. Now looking into acquiring a newer machine to continue moving from XP to Mint before XP becomes, in April, more of a liability than it already is.
Hopefully Flash will cease to be in the near future.