Did you ever download...
Thanks much for the detailed response - I should have been a tad more so in my question (that is to say, I have done most everything you've suggested I'm afraid). I was trying not to create a monstrous post. Suffice to say, all of the 'basics' have been covered, and then some. I'll run you through it though. Regardless, I appreciate all the suggestions! I haven't actually used process explorer, I will give that a go.
First off when the other browsers were no more responsive than Firefox, I uninstalled them. They were only for testing. I generally use only Firefox and I've done three clean installs (after removal) of that, as well as Flash (using removal tool). I deleted all content each time, ran it in safe mode, created an alt profile (that was suggested elsewhere), ran it as admin., tweaked a couple of the "about:" settings I found in forums, you name it.
I am convinced the browser and flash are fine.I run the identical version of firefox and flash on my other machine and it soars.
There are nearly no programs on this machine as yet, it being a new install (so nothing to remove) - primarily diagnostic tools and malware detection/removal I've added since the issue (SIW, malwarebytes, hjt, etc.).
I use CCleaner regularly, out of habit (pretty much every time I run a machine). But again, this machine has virtually no history to speak of yet, so I've yet to download it. Soon.
Device manager is a go - no issues.
Pure Networks (for my router) is the only
non-windows service running in msconfig (as I mentioned, this is a new install, there's really nothing running on it yet)
I have no virus protection or firewall running yet, as that has interfered in the past with my streaming. I needed a raw test to see if the integrated graphics would handle streaming Flash. If not, I'd stop there, and get a vid card before proceeding. The machine wasn't online before that. I use my other machine to retrieve updates, download, etc. simply because its faster.
Now, though I very much doubted that couple of minutes on my youtube page would've infected my machine, I went ahead and ran MalwareBytes (full scan), HJT (total of only 16 entries there - none of which unexpected) and Spybot (full scan) just to be thorough - all squeaky clean.
Currently 0% fragmentation on the drive. One run after the new install, and another after deletion of browsers and addition of detection software.
As per the CPU usage, here is one fluctuation watching a flash vid on youtube with firefox (heh, ignore the wordpad, I was typing this as I went);
*NOTE - the values of Firefox and Plugin container (the firefox counterpart) are constantly fluctuating and exchanging rates of consumption, always totaling just shy of 100%. (probably is a true 100%, but task manager and explorer borrow a bit when they are active)
Here is a shot of IE under the same conditions;
...and the ultimate result with ANY browser viewing a flash vid;
So, there we are. (??)
New install, fully updated, clean as could be, defragged, up-to-date drivers, virtually no unneeded services running, clean inside (no dust, etc.), same connection, network, browser and flash version of a quick machine. Ugh.
I currently am leaning towards either a driver issue (in spite of the updates) or some sort of hardware problem/conflict at this point, but frankly am not sure how to determine which/what. Another machine of mine had a VERY similar problem for the longest time, and it all turned out to be due to an m-audio driver (for my sound card). Reinstalled that with the latest version and the problems vanished never to return. I assume it had become corrupted, not sure. I have now completely disabled the onboard realtek chip in case it was somehow conflicting with the Creative card, but to no avail.
Again, appreciate all your suggestions, it made me rethink what paths I had taken if nothing else. There's no doubt more I've tried and have forgotten to include. I've been at this for days. Sadly, I'm not sure what this leaves me.