How do U undo installation process?

[dragonfly22588]

So, I just built my new system and everything seems to be running fine but I realized just as I was finishing the installation for Windows 7 that I was installing the 32 bit version (silly me I thought you would be given an option to choose once it started). Anyway, I'm at the screen where it is asking me to create a user name and name my PC for the first time. I tried restarting the computer with the 64 bit version but it just loads back to the setup screen. What is the best way to get the 64 bit version installed?

 

[smorizio]

So, I just built my new system and everything seems to be running fine but I realized just as I was finishing the installation for Windows 7 that I was installing the 32 bit version (silly me I thought you would be given an option to choose once it started). Anyway, I'm at the screen where it is asking me to create a user name and name my PC for the first time. I tried restarting the computer with the 64 bit version but it just loads back to the setup screen. What is the best way to get the 64 bit version installed?

boot up from the windows 7 cd again when it start go into advance mode and delete all the partion on your hard drive and then reboot and restart the install.