As CountMike said, you cannot have more than about 4GBs of RAM on a 32-bit system, however, you can upgrade to 64-bit. There are many guides online, but you will need a x64 bit based processor. To check if your processor does support a 64-bit version of windows 10 pro, you can go to start > the little settings/gear icon > system > about and it should say there what OS you are running and what you could be running. To "upgrade" There is no actual upgrade path. You must perform a clean install on your PC, which is where you completely reinstall windows, however this time having a 64-bit based OS. It really is a pain in the backcheeks, but it's the only way. First of all, you need to be sure you have an activated windows key. Without this your new OS will have less features and will constantly give you a notification, so make sure you write this down on a few different pieces of paper so you can be 110% sure you wont write a typo key and be stuck/lose it and be stuck. Once you have the product key, you will need a USB flash drive with a minimum of 8GBs storage. You will need to download this windows 10 bootable file :
https://www.microsoft.com/en-us/software-download/windows10 onto your flash drive. Since you currently have a 32-bit system, download the 32 bit tool for now. Once in the app, select “Create installation media for another PC" Choose your language, edition of windows 10 and architecture (32bit/64bit) obviously choose 64-bit (x64) Reboot your PC, boot from the USB drive and install windows onto your disk. This could take a while so sit back and get comfortable. Once the installation is complete, you may follow the instructions that prompt you. You will get prompted with 2 requests for putting your product key in, I recommend typing your key in these times. You may skip them, but it will be a lot harder later on to activate your key. In other words, its just more effort if it's not done automatically.
Hope this helps! Unless of course in the unlikely event of you having an x86 based processor, which means I would of wasted all my time here.
Here's the guide that I put into my own words: http://www.howtogeek.com/228042/how-to-switch-from-32-bit-windows-10-to-64-bit-windows-10/
If you did what I said and have the right processor, you should have a 64-bit edition of windows 10, and ALLLLL of your RAM! WOOP
problem solved.
P.S
In your new 64-bit system, if you wouldn't mind selecting this as the solution that would be great!
Good luck!
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