I have Windows Vista but I want Linux but I don't know what to get or how to work it.

You can goto http://distrowatch.com/ and pick an .iso to download. Then burn that disk image to cd or dvd and reboot to try it out. (One note, burn .iso's slooooowly and do a md5checksum on the .iso file to make sure it downloaded correctly)

I strongly recommend the use of write-once CDs and DVDs. Some computers such as Dell computers will not boot from an image on a rewritable medium.

Make sure to have your computer set to "boot to cd," or watch for the prompt to "press any key to boot..." etc during startup.

With vista, make sure you have a disc burning program that can burn .iso's, such as ImgBurn. Besides that, just pick a distro and give it a try. The online documentation (from it's web site) for the distro should tell you everything you need.
If you got any more questions just ask.

Cheers

ubuntu is a very good choice for a newbie.

When I was ignorant of these things myself and looking for a good Linux distribution, I followed similar advice and wasted a lot of time digging through distrowatch. It just got me more confused.

I personally think Mepis is the least confusing for a Linux beginner switching from Windows
https://www.mepis.org/
BTW, despite the "buy" link on that page, Mepis is available for free download and unrestricted use. Buying the CD might be more convenient.

On many images on several different computer with different CD and DVD drives, I never had a problem simply letting ImgBurn automatically select the settings. I don't know enough to tweak them and fortunately I never needed to.

On many different downloads of .iso files, I never got one with the right size but wrong contents. With FTP and HTTP downloads of very big files, I very often got files that were far short of the correct length. But that is easy to spot even without md5. Bit torrent is a lot more robust. I've never seen that think it was done when it hadn't delivered a complete and perfect file.

Before I started using Linux, I found the instructions for checking md5 on downloads very confusing. Most of those instructions are written by and for Linux users. The tools are available and easy for Windows users as well, but decent instructions for which tool to use and how to use it may be hard to find. I've forgotten what I finally figured out about checking md5 on Windows and usually I don't. Skipping that hasn't been a problem yet.

I strongly recommend ImgBurn
http://www.imgburn.com/
It is free and works real well and is less confusing than typical CD burning programs.
In any CD burning program there is a correct operation for burning an .iso and there is an incorrect operation. There is no standard for naming those two operations and lots of beginners pick the wrong one.
In ImgBurn, the correct operation is called
Write image file to disc
The incorrect operation is called Write files/folder to disc.

If you can't tell which is the correct write operation in your CD software, figure it out before using that software. If you only found one of the two write operations in a Windows CD writing program, it is almost certainly the wrong one (switch to ImgBurn). That "wrong" operation is the one that should be used when you are using a CD or DVD as backup media for files from your PC. It is wrong because saving a .iso on a CD as a backed up file is not the same thing as burning a .iso to a CD as an image.

If you are trying to find the right distro, good luck. I have been using since suse 7.2 (around 2000). I have been trough many many distro's trying to find just the right one. Right now I am on Fedora core 11, was on Ubuntu / Kubuntu for about 4 months (the longest running install for me yet), when i was in Iraq in 2003 I installed Redhat 8X, because the Army IT folks kept scrambling my ether net registry on windows, I fixed them ha ha.

I strongly recommend using live versions first. Lets you test drive before you install. Also look at linux mint.