Ok hi again haha! I want to actually get rid of Windows 8. I have no use for it. I am just going to use Windows 7 from now on. I want to install Ubuntu on my Windows 8 partition that I have on my hard disk. So basically, I would like to replace Windows 8 with Ubuntu. How can I just erase Windows 8 and just install Ubuntu on it.
There you go, simply install Ubuntu where Windows 8 is. However, before proceeding (this is more likely for future users, as this one has likely been decided) be sure to fully backup your computer. There are free backup apps available, such as Macrium Reflect & EaseUS Todo, which are popular & easy to use. Be sure to create rescue media for recovery.
Ubuntu will run nicely beside of Windows 7, at this stage I recommend to go with Ubuntu 14.04, of which Beta 1 has already been released & the full release will be due in April. This will be a LTS (5 year support) version, unlike the short releases (6-9 month support), so at least for 3 years an upgrade won't be necessary. As by then another LTS release will be due. This also applies to Ubuntu based versions of Linux Mint & other Linux OS's that's built upon Ubuntu.
The OP here isn't the first to desire to purge their computer of Windows 8 & won't be the last.