Issues with my HP-Envy

[FDITUP]

Issue #1

I was looking to upgrade my family PC, as it is getting on in years. I took it apart to confirm that the CPU wasn't soldered on (I didn't know; I had never worked on an all-in-one before), and saw that it was not soldered. I disconnected the fan, blew the dust out, put it back together, and noticed that it was running even slower than I was accustomed to. I remembered I hadn't reconnected the fan, and did so. It was still running slow. Upon opening task manager, I noticed that the Hard drive was running at 100% while idle. This must be what was causing the operating system to be so laggy; even control panel took almost 15 seconds to open.

Question #1: What can I do, short of a factory reset, to solve the hard drive use issue?

EDIT: The drive use issue seems to to wind down after the computer has been running for 15 minutes or so. It could very well  be just the result of windows launching off of an old hard drive. I don't use this machine very often, so I'm not sure.

Issue #2

Back to my attempts to upgrade this machine. I want to upgrade the CPU, but I suspect the built in cooling and power supply will be my bottleneck. The current CPU ( i5-6400t)  has a 35W TDP. The CPUs that I'm looking to upgrade to start at 65W TDP. Also, I'm not sure about these socket types. Is there a compatibility issue between LGA 1151, FCLGA1151,  FCLGA1151-2? 

Question #2: Is there a CPU that I can upgrade to that would be worth the trouble? If there are many, how can I distinguish between an incompatible and compatible CPU?

Issue #3

I want to replace the storage with an SSD as well. I want the drive be at the factory state of the HP-Envy when I install it to ensure maximum compatibility. I expect that I can achieve this with the HP Cloud Recovery Tool by setting up the external USB (On the HP-Envy) for the reset, replacing the internal drive, and then running the Cloud Recovery Tool on the HP-Envy.

Question #3: Will the above solution work? If not, how can I set the new internal SSD to the HP-Envy's factory state?

[itsmyname]

@FDITUP -- Is this your computer: HP ENVY 24-n014 TouchSmart All-in-One Desktop PC Product Specifications | HP® Customer Support

That page lists: Intel Core i7-6700T (Skylake) 2.8 GHz Quad Core

as a compatible upgrade (from your 2.2 Ghz to 2.8 Ghz).

Is a 25% upgrade in speed worth spending your money?

Part Two: if you use free "disk-cloning" software, such as "Macrium Reflect", it will copy all the partitions from the current disk-drive to the SSD.  Hopefully, one of the copied partitions will be the partition used for a "factory-reset". So, if you can force your computer to boot into the "factory-reset" mode, that should be what you want.