Hi V444nko,
My name is Troy and I am an Independent Advisor and Windows 10 Expert. I'll be glad to help you.
your PC is bellow the windows 10 system requirement. while windows 10 give better experience compare to other previous windows version. with the your laptops current specs you won't experience the same experience as compared to modern hardware. I suggest to just use windows 8.1 with that and do a clean format.
you can refer this link for information.
https://support.microsoft.com/en-ph/help/402814...
While you're at it I suggest to upgrade your laptop's HDD to use SSD instead. that was a cheap and great upgrade specially with old laptops. it will make your laptop feel snappy and super responsive. just last night I upgraded my 7yr old asus laptop with a kingston SSD for 20USD and now its very responsive. can boot in less than 1 minute.
you can refer to this link on guide an information on how to change your laptop to use SSD.
https://www.youtube.com/watch?v=z8OJTZGdVq4
Hope this helps. If you still need assistance, feel free to ask.
Disclaimer: This is a non-Microsoft website. The page appears to be providing accurate, safe information. Watch out for ads on the site that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it.