My newish PC keeps freezing, it boots to desktop & lets you open Chrome, Word etc but then after about a minute stops working & needs an off/on reboot before it usable again but its always fine after this (until powered down again)
I’ve searched the net & done the following that I’ve found:
Updated drivers (a couple were needed but most said they had the most up to date for the devise)
Uninstalled the only program that I thought might give issues (it came with a Chinese wifi CCTV camera)
Both of these didn’t fix the freeze issue.

Secondly I’ve fitted a 2TB conventional HD & everytime I double click on it there is a delay while it seems to ‘build’ a menu of its contents (address bar gradually turns green from the left) is there a way of storing the menu so its usable quicker (previous computers HDs seem to do this)

task manager and see what’s consuming resources.

Are you getting a Blue Screen or other error messages when the freeze occurs? If not is it just completely unresponsive? Any HDD activity?

As Del says worth running Task Manager (or better Resource Manager) and keep an eye on what’s running and if something is consuming a lot of resources.

Might also be an over-heating or CPU voltage issue, try running something like https://www.cpuid.com/softwares/hwmonitor.html to keep an eye on the temps/voltage and check against vendor support temps (especially CPU but also GPU temp, you might need a graphics card app for that though)

As for the slow display of drive contents, could be a number of things (indexing, bad blocks on disk, dodgy app etc.) Is the 2TB your only drive or is it a second drive (and if so does the primary drive have the same delay)?

Is it an off-the-shelf PC or a self-build?

If the former, back up your data (which you do already, right?) and factory reset it. If the problem persists, it’s broken, send it back under warranty.

FIrst question – is the fan running?

Blue Screen – had one once, ‘thread stuck in device driver’ not had this since updating drivers.
Task manager shows nothing untoward, under 14% CPU usage, over 7Gb of memory free.
Doubt its CPU overheat as it does it so soon after starting, then not again after reboot – I’ll try a monitoring program to check.
C drive is a 256Gb SSD so no delay, the 2TB drive is a WD 7200 second drive used for storage only.
It was a new PC bought secondhand but unused from Ebay, its high spec i5 quad core with branded PSU & >£240 graphics card etc.
Everything is backed up to a separate drive in a caddy – factory reset might be a last resort.
Fan runs fast at start up then slows down but still runs.

If you’ve got backups then factory reset is probably easier than farting about trying to trace it.

Also,

https://www.memtest86.com/

Wipe it, update the drivers – I use Driver Booster ( clicky ) and use Ninite ( clicky ) to get the most-used software back on your machine quickly.

Right, running monitoring prog.
Struggle to get CPU temps above 42C & barely any volt drop even when running processor @ 55% fan speeds up during this.
GPU software shows nothing untoward & graphics are perfect even when
Mem test runs without error.

Its almost as though something is not shutting down correctly through W10 powerdown but is fixed by a forced reboot.

Next time you shut it down, hold Shift when you click on Shut Down. See if the problem persists when it comes back up.

Why are you shutting it down, anyway? Why not just leave it to go into powersaving?