Can my Inspiron 15 3000 (3567) be upgraded? Extremely slow

I purchased the Inspiron 15 3000 series (3567) which has a i3-6606U processor with 4GB DDR4 ram.

This is the slowest computer I have ever used. When I (mouse) click on a icon (like to start Chrome, or open a program (Word, etc.)) it takes more than 5 seconds for anything to happen. Many times I think the "click" was not firm enough or didn't get recognized, so I click again. Then 5 or 6 seconds later two of the same programs open. Even doing Ctrl+Alt+Del is slow to open.

First I thought there might be some faulty/damaged software responsible, so I reformatted the hard drive and loaded Windows 10 fresh install. However the computer is still as slow. There is no way this is normal or acceptable. I should have returned it when I first bought it, but I don't use the laptop much (at first just for trips) so it was not something at the top of my to-do list. But I can't continue to use the laptop like this - 

• Is there a possibility of upgrading to a faster processor?
• Is there possibly a Dell trade-in program where I could upgrade that way to a more usable computer?