How can I see what my PC is doing AFTER boot

BootRacer says bootup time is 68 seconds. This makes sense with the stuff I have. But after that the HDD activity light burns constantly for just over 3 minutes (I know from the timer for the coffee plunger) and the machine is extremely unresponsive. Almost useless.
Trying to use Resource Manager (which just about uses up the 3 minutes to open up) just shows things such as svchost, etc., which is not very informative.
For what it is worth, indexing is off for all 5 HDDs.

Is there anything I can use that will give me report when I say it can stop monitoring?

Get MS Sysinternals Process Explorer, unzip it, and add a shortcut for Process Explorer to your Startup folder.
This should display the Process Explorer window sooner, while your PC is unresponsive and you can't click on anything to see what's running.
https://technet.microsoft.com/en-us/...rocessexplorer

Run Process Explorer and sort the window so it displays the most used CPU at the top by clicking on the column heading.
Restart your PC and see if it shows what program is using the most CPU, and causing your Disk activity.

If the most used CPU is not what is causing your HDD activity, you can add columns for Process I/O in menu/view/Select Columns.
You can then sort by Reads, Writes, etc. to try and find the culprit.

If you need a report you might need to use other tools such as Windows Performance Monitor or Sysinternals Process Monitor.

It was Nero Media Home. Reading and writing for 3 minutes.

Glad to see you got this solved.
Did Process Explorer help you find it ?

While I was waiting for a reply I did it the hard way - live monitoring disk activity in Resource Monitor while booting - and saw it.
And then spent more than an hour to get the LG BDplayer to be happy with Windows' built-in DLNA server. Uninstalling Nero Media Home did not re-enable Windows Media Player Network Sharing Service.

Thanks for that info.
That could help others trying to solve a similar problem.
:)