Since somehow i can't manage to install ubuntu from cd (it is broken) can't install from usb (wont boot from usb drive larger than 256mb nor will UNETBOOTIN work from that usb), and i don't have the skills to install from pxe (network install). So is there a way to install (clean install NOT A DUAL BOOT) ubuntu from windows hard drive?
p.s. i might be there is some option in unebootin to "install on hard drive" but I am not sure will that remove windows from my hdd?
Short and quick answer (actually you answered it!): Use a netinstall image which is smaller than 256Mb. (https://help.ubuntu.com/community/Installation/MinimalCD)
Simply you will need the help of another newer computer. Transfer the hard drive of the old one to be the bootable master at the newer one. Boot the installation media, install the distro. and then return the hard drive again to the older and boot it again. Checkout this story answer.
There is (as mentioned by @frantique) a minimal install option, which you can find on ubuntu.com
