Yes, you can. The laptop has already been register with 10.

Only way you can't go back to 10 for free on a PC/Laptop that has already had 10 on it is if you change motherboards. Hence the MS rule that 10 is free on that PC for the life of the PC (motherboard).

Hard drives can be changed out, no problem.

Yes, again, you can put 10 on it, and it will activate.

https://www.microsoft.com/en-us/accessibility/windows10upgrade?tduid=(14c348e893a91089cb2980533c6ee123)(256380)(2459594)(TnL5HPStwNw-0FBZfNm6YPFXNhiu3o52rA)( 

long link but it may suit you.

That's cool, Paul. I didn't know about that.

that would be them relying on you to be honest about needing accessibility aid. do tape up your cameras though.. you know win10 spying on you and all

They'll know if you've been using any such aids already.  'Course, I suppose you could go blind at any moment.

I'm guessing that qualifying is a tad more complex than just taking your word......

Thanks guys. I found the Windows 10 ISO file at Microsoft. Downloaded it, installed it, and it activated just fine. Was gonna use Windows 8 for a bit, but it proved to be highly annoying. Had to turn off a bunch of privacy settings in 10, but otherwise I'm set. 

Hey everyone. One last question. It seems to me that Windows 8 booted quicker, and woke up from sleeping faster than 10. It's only a 2.2 GHz dual core Celeron machine, with 4GB DDR3 for RAM, so I am curious if Windows 10 is too much for the system to handle. :/

Windows 10, on clean install, is much faster than Windows 7 or 8. Now as far of the rest of it, that's another question, the UI and a lot of features of course suck.

I have a Dell I7 that had Windows 10 on it kona, with 4GB of DDR3 RAM, and it was really slow to me. So I just upgraded it to a Samsung EVO 1TB SSD, and now it's a LOT faster! Your system specs should be fine with Windows 10, but you also might consider putting an SSD in, to me it made a world of difference. 

I have thought about a SSD, but sadly it's a low end laptop, so there's no ports to access on the bottom to change out the hard drive or RAM. Even the battery is non removeable.

Odd, a laptop that has to be thrown away if the hard drive fails?

Who is the manufacturer?

Most laptops are that way. The only way to do anything is send it to the manufacturer, and it is limited. That is how you can carry it everywhere. It is called sodering.

The laptop is a Asus X551M. Found a video about how to change out the drive, it evolves taking the whole bottom off the laptop. Way to much for me to attempt. 

Are there usb external ssd drives. That would work