Busted hp laptop

Good day,2020 my wife surprised me with a laptop for a birthday present, so took the laptop on a contract at vodacom,the hp laptop isnt being used alot,the laptop was always very slow,this year recently the laptop didn't wanted to boot up,my wife contacted Vodacom and someone told my wife we can take the laptop to any vodacom store,we drove our petrol out to vodacom at canal walk and we were told to contact platinum warranty,which we did.... The laptop was collected and platinum fitted a new hard drive,that's the report that came back with the laptop,there were basic windows 10 loaded,i received a notification to update to windows 11,i did... After a while the laptop didn't wanna boot up same as before,we send it away again and i requested they check the ram in the laptop,the send the laptop back to me saying i loaded windows11 and thats why the laptop are not booting, i got it to boot,loaded windows 10 and its doing exactly the same as before the new hard drive was fitted,I'm so frustrated that i opened it up on sunday to take a pic of the ram so i can go buy it myself!! Please help!!!