I installed Ubuntu and it isn't working properly. I have tried everything to fix the issues such as not playing dvds or running windows software through Playonlinux. I tried to reinstall windows from a windows disk and it keeps giving me an error that I don't have enough space on my hard drive to install. I have tried booting from the disk as well with no success. I really just want to reinstall Windows so I can have piece of mind that my laptop will run properly. If anyone out there can help me it would be much appreciated.
Have you ever tried installing ubuntu-restricted-extras?
sudo apt-get install ubuntu-restricted-extras
Also if you want to delete everything. Create a bootable USB, install wipe and wipe everything
sudo apt-get install wipe
The community here on AskUbuntu would be more than happy to help you with any issues you have with Ubuntu, and can get Ubuntu running the way it should. If you're simply not satisfied with Ubuntu, I would recommend checking out the link Florian gave to get Windows back on your computer.
I'll address some of the issues you mentioned. For example, you said that you couldn't play DVDs. This is likely because Ubuntu doesn't ship with any video codecs installed in Totem, the default video player. This is because the codecs are typically proprietary. I recommend getting VLC Media Player. It's served me well, and comes loaded with it's own decoder. You can get it in the Software Center, through Synaptic, or by opening a terminal and typing
sudo apt-get install vlc.
As for not being able to run Windows programs with PlayOnLinux, you actually would use an application called WINE to run Windows programs. You can get it by opening a terminal and typing
sudo add-apt-repository ppa:ubuntu-wine/ppa, followed by
sudo apt-get update, and then
sudo apt-get install wine1.7. WINE is a pretty large package, so it might take a while to download. Once that's finished, you will be able to install and run most Windows programs as they were originally intended.
Finally, if you're still not happy, I recommend firing up you're live drive (the LiveCD or USB drive you installed Ubuntu with) and opening up gparted, the partition editor. When it's open, delete both the ext4 and linux-swap partitions. If you want to, you can fill in the unallocated space with an ntfs partition, and then running the installation of Windows.
The reason the Windows installation said that you have no disk space is because Windows cannot read ext4 or swap partition types, so to it, those were unreadable spaces on your hard drive that it can't format or use, and there was no unallocated space to throw down an ntfs partition in.
Hopefully this helped. Remember, if you ever want to stick around with Ubuntu, there's a ton of fine people here who will always welcome your questions. :)