So, as @karlsnooks and @golden had said, I downloaded an ISO file from Official Windows 7 SP1 ISO from Digital River « My Digital Life
And using a Windows 7 USB/DVD Tool, I burned it into a USB stick.
Now, when I boot from it, I get to the Window home screen, and when I proceed, I get this message:
"A required CD/DVD drive device driver
is missing. If you have a driver floppy disk, CD, DVD, or USB flash drive, please insert it now. Note: If the Windows installation media is in the CD/DVD drive, you can safely remove it for this step." <Browse> <OK> <Cancel>
When I browse and point it to the Boot folder, this message comes:
No device drivers
were found. Make sure that the installation media contains the correct drivers and then click OK.
I'm currently running Windows 7 Ultimate x64. What I'm planning to do is FORMAT my whole PC and do a custom install of Windows 7 Ultimate x64 again.