Why is Windows 10 so slow?

Right-click task-bar > Task Manager, check CPU/Memory/Disk usage, click on top of each to sort from high to low and figure what using up your resources. If they're useless programs, probably best to uninstall/disable them. HP also packs a bunch of bloatware that don't do your laptop any good. I highly suggest reinstall Windows 10 from a clean image, download the media creation tool from Microsoft (see link) and follow through to make a bootable usb drive. Guaranteed it will run much better with bare Windows without the added junks.

If you're not comfortable doing it, then at least uninstall all the HP bloatware from Programs and Feature. Also in Task Manager, on the startup tab, you can choose to disable unnecessary processes from booting up. Most of them are not needed when boot, but you might want to right click on it and choose "search online" to see what it is to be sure before disabling it.

Finally, if you really want to speed things up, upgrade to an SSD instead of the regular spindle drive that comes with it.

If you are running Avast and HP Support assistant - that could be why.

What other vitally necessary things have you uninstalled?

What speed should a notebook run at? Why do you think it is slow?? What apps or Internet pages are you testing on??

Is HP Support necessary? Should I run the computer just on Windows Defender?