Wndows 10 x86,x86 based PC but x64 based processor,can it go x64

Hello,
I have a 32 bit windows 10 and x86 based pc but x64 based processor,originally it was a windows 10 64 bit and x64 based pc but my hard drive broke and got bad sector,it got fixed my a computer fixer but he installed 32 bit instead of 64 bit,i have a windows 10 x64 installtion media but when i run it it says it cannot run on my pc,i really wanna go back to 64 bit because only 2.60gb of my ram is usable out of 4gb

CountMike said:

It could be because of some driver or other HW but if processor is 64bit (and it is), 64bit OS should run on it without problems.

But i cant run the windows 10 64 bit installer it says it cant run on my pc

I cant run the windows 10 64 bit installer it says it cannot run on my pc

Do i need to boot from BIOS or something if so will i lose my data

Also i think there is a problem with my RAM,windows 10's 32 bit ram limit is 4gb but why only 2.60gb is usable

there are drivers available for my acer laptop but i think it needs 64 bit to install

but how to do i install windows 10 64 bit,i cant even run the installer