remove dual boot & switching boot drive & fan problems post factory reset

Hi guys, was hoping for some help. Situation is:

Factory reset my Alienware m18x r2 laptop. Had a look and turns out for some reason I've had a windows folder on my self installed SSD drive, with the main windows partion on the factory installed hdd disk. Since restoring my laptop i've done the whole windows update etc.

Wanted to confirm, would the best option be too switch main boot drive via disk management first to the SSD, then simply using disk management to delete the original boot drive? I want to erase everything from the non SSD drive. From what I understand, my other option is to delete the windows partion on SSD drive, format it etc then copy the image from original drive onto it, then delete the drive C. the reason why im potentially considering this method is because not only do i have windows folder duplicated, but also every other folder and im wondering whether i might potentially delete something i might need in the process.

Finally, after doing my factory reset, my laptop seems to have had its fans usage go through the roof (doing nothing other than standard browsing, no games etc) - anyone have any idea why?

apologies for n00bie questions, this is the first time i've done factory reset.