My friend wants me to upgrade their system so I had them buy an IWill KK266, a 1GHZ Athlon, 256mb Crucial RAM, and a new power supply, since the old system is a Pentium II 233 and the old power supply probably won't work with the Athlon board. Windows is already installed on the hard drive and is configured for the gateway motherboard/cpu/RAM. When I swap these components, will Windows still function properly or will I have to format the drive and reinstall Windows? Is there any way I can prevent weird errors from happening after I swap the components? Thanks in advance!