so i have a really old pre buit pc, and im really just trying to keep it alive until i have enough money to build myself one. the pc i have is a gateway dx4840-11c. this pc is carrying a i3 550 lga 1156. i have found a cheap used i7. can i replace the i3 with the i7. would there be any issues with this? would it be compatable with my mobo/bios. i read some where that the bios on prebuilts tend to be locked down. my pc is so bad that i can only open one program at a time. if i do try to use more than one program at a time it just begins to stutter.