You want custom which will format the drive and wipe out all info. Upgrades frequently have problems. Look here and you will see many people looking for help that upgraded and now have serious problems.
Joe
thank you joe, i think i'll install custom clean installation, that's better.
& ya i saw some people asking help for some upgrading windows
now i just want to know, is there anything special in installing windows 7 or it's just a wizard and next next ... so on, because it's the first time to install windows 7