Replace or upgrade???

[ucrdem]

5. You can probably get a performance boost from upgrading to 10 pro.

IIRC 7 home premium is a 32-bit version but it looks like your system can probably handle a 64-bit OS in which case you can download the 10 pro installer to a USB drive and simply add it to your existing boot store. In other words if you create a partition for it and install it now, before you even wipe your old drive, it will create a boot menu automatically, giving you a choice to boot into 7 or 10 at start-up. You won't be able to activate it without a new license but in most cases you won't need to:

https://www.microsoft.com/en-in/software-download/windows10

p.s. if it gives you grief about the COA at any point either click "skip" or if that doesn't work try your 7 COA.