Some remarks - as you also noticed and described... McAfee can indeed cause problems on some systems while on it works perfectly on other systems. This is a known fact.
Also, as I read here, you actually "overloaded" your system with all kind of extra scans, registry tools, System Tweak tools etc...
Keep in mind that they may cause more problems than anything else.
Especially registry cleaners - which I don't recommend at all. It's not the first time that someone had to reinstall Windows because they ran a registry cleaning tool which actually caused a corrupted registry instead of "repairing" it.
Basically Windows Standard settings are still the best. Why starting to tweak it? Using registry boosters and other tweaks do change basic settings in Windows - Some do disable some services, which are actually required to run some programs properly, disable other components which are actually also needed - and then afterwards people start to complain that their Windows doesn't work as it was supposed to work?
Unless you know EXACTLY what you are doing, what you are disabling... but unfortunately this isn't always the case, since many of these so called "tweak tools and optimizing tools" have the button which says: "Speed up my Pc" or something similar. Then they click it -- but don't know what it exactly did.
I tested same apps and same McAfee on another less powerful machine and performance was great with Task Manager of 1% only of CPU consumption.
I guess that less powerful machine was also less tweaked and not overloaded with all the extra tools
Anyway, when I looked at your HijackThislog, I see there are a HUGE amount of programs/tools running in the background. The more tools you add - starting up with Windows - the slower your system. And yes, this also counts for the so called "speed up tools".
McAfee is already known to slow down the system a lot. If you install other similar apps on top, also running in the background - actually doing the same thing as McAfee does (do you also clean your house with several different vacuum cleaners?), this may cause the extra slowdown and may even cause compatibility problems.
Please read this page how to improve system performance in a "healthy" way: http://users.telenet.be/bluepatchy/miekiem...owcomputer.html
Don't forget to read the link there: "What really slows down Windows".