I have decided to switch to Windows. I would like to completely remove ubuntu, and all the other files on my computer. How do I do this? I basically want to wipe my computer clean.
formatting does not delete the data, you need to write data to the drive. Boot a live CD and either write zeros to the hard drive with dd or use a utility such as shread
dd if=/dev/zero of=/dev/sda iflag=nocache oflag=direct bs=4096
or use a utility such as scrub
You then format the hard drive and install your os of choice
That would be reformatting the drive. You can probably do this automatically when installing windows. Otherwise, you can also use a utility program do do it ahead of time. You could boot an OS from a live DVD, to get a running OS without having your harddisk mounted, and then use a disk utility from that live DVD's OS to nuke the the disk. Better make sure you don't have any data.
If all you're after is clearing the existing data so it won't interfere with a clean install of Windows, creating a new partition table and partitions along with formatting the partitions is sufficient; Windows installers at least up through 7 would do this automatically if you answer the prompts that way.
If you're concerned about ensuring data on the existing partitions can't be retrieved, you need to use a "data shredder" or "mil-spec erase" utility; in my experience, these are often bootable Live CDs with a limited Linux OS and (often auto-running) utilities tailored specifically to erasing data. I have one called "Boot and Nuke" that boots from CD and erases all hard disks attached to the system with a secure erase. Due to the nature of secure erase (overwriting all of the data surface of the device, many times, with patterns and random data) this process takes a long time (overnight, at least, with modern terabyte class drives).
Unless you're trying to remove evidence of a crime (doing so is a crime in itself!) or national security related data, this is probably an unnecessary length. For most purposes, it's quite sufficient to boot from the Windows media and tell the Windows installer that you want to erase the hard disk and partition it from scratch.
I will help you to wipe your hard drive such that it is completely indistuishable from a new hard drive. Asking us how to reinstall Windows is "off topic" for this site. Please rephrase your question to omit that aspect of your request.
The super simple way to wipe your hard drive to like new status (no partitions at all), is to boot your computer to literally any ubuntu Live Boot boot (media) CD/usb-flash. It doesn't have to be remotely up to date, so whatever you installed ubuntu with should be more than adequate.
Once your computer is booted to a live boot CD you merely open one program already on the live boot media. It is called Disk Utility, and it will do exactly what you want to do with absolutely no thinking or grief. You don't even have to open terminal! Detailed step-by-step instructions below for both opening the utility and what to do once you have it open, but my guess is that you could adequately wipe your hard drive with that utility even without the following instructions.
Dumbed down usage instructions:
- Open Disk Utility (press the windows key on your keyboard and immediately type DISK and then press enter)
- First select your hard drive from the left side menu within that window.
- Then maximize the window so you can see all its options.
- Choose the lower right option called FORMAT VOLUME.
- In the window which appears, change the selection in the drop-down menu next to "TYPE" to EMPTY. (please don't try to give it a name. You cannot since there is no partition there to name)
- Press format, and the drive will be completely wiped, devoid of data, partitions or even partition tables.
This type of erasure is not quite the same as SHRED nor is it as time consuming. If you turned your drive over to the CIA they could probably recover all your data before sending you to a secret prison... or perhaps afterwards, I won't speculate. If you want that type of file destruction and have the time, I recommend shred instead. The method I've described is much faster and will ensure that windows will install correctly.
One last item I'd like to mention. When you first open Disk Utility, it will offer you a peek into the "SMART" status of your drive, and can tell you if your hard drive is healthy. All operating systems which install to hard drives rely upon the hard drive working correctly. If you have had an unhappy experience with Ubuntu, there's a good chance the cause was actually that the drive is sick. In which case, Windows won't work right either.