hi. if i want to replace a CPU, do i have to reformat my computer for it to work properly? or will i just have to place it in and everything will be ok?
Generally you want to check if your mobo will support the new cpu.
Most of the time a bios update is required when upgrading a cpu.
If you already have the latest bios version you can skip that.
No! you do not need to re-install the O/S.