Where you purchased the computer from doesn't matter.  What brand (Dell, HP, Asus, etc) doesn't matter.  Windows doesn't come from Microsoft with any of the bloat.  The PC manufacturer adds that.  They may make it difficult to remove or appear necessary but it is not needed.  Sometimes it may be necessary to have another internet enabled device close by so you can search for instructions while you are removing the bloat from the PC.  In you situation I would determine which version of McAfee you have installed on your PC and then search "Windows XX remove McAfee XX".  Read through the various search results and you'll probably find it tells you to remove the 3 or 4 different McAfee products that get installed in a certain order.  Once that is complete download Malwarebytes.  DON'T PAY FOR ANYTHING.  Install it and do a complete scan and allow it to remove the junk it finds. You'll be amazed how well your PC can work.