Windows 7 Install HELP!

Okay, so I downloaded 64bit Windows 7 Professional image, I mount it. Attempt to run autorun. Since I am using 32bit system currently it says that its incompatible…..But I checked, I am compatible with 64bit system. Does the 32bit version have a 64bit install option?
Note:
In case you were wondering I ran it from Desktop, not from boot.
Answer #1
You can only upgrade from 32bit to 32 bit, and from 64bit to 64bit. you cant mix those when upgrading an existing windows installation. If you want 64bit you will need to burn that iso and do a clean install from boot.
Answer #2
You have to boot it for it to work
Answer #3
You cant install through the windows environment, you’ll have to boot from the disc in order for it to work. Restart PC, press delete to get into BIOS and change boot order to CD/DVD first
Save settings, allow PC to boot from disc and follow prompts
Select partition to install (format if necessary)
Enjoy