Windows 7 - Trouble with Google Chrome

I am trying to download and install Google Chrome, it all seemed to be going well and then I got this error
Your installation failed with the following error(s). Please click below for details.

• Error 0x00000003
  
  
  You're seeing this error because you're attempting to download Google Chrome for your user account, but the browser is already installed for all user accounts on your computer. You can ignore this error if Google Chrome is already open on your computer.
  
  

Above in the blue it says error 3.
I don't understand what they are saying about user accounts. Can you help? Thanks.

Have you already got Chrome Installed?

Perhaps it just isn't in the Start Menu:

Go to here:
C:\Users\UserName\AppData\Local\Google\Chrome\Application

and select chrome.exe

Now, right click and select Copy.

Put it to to your Desktop and right click chrome.exe and chose Create Shortcut. Now rename the new Shortcut to Google Chrome and drag it into your Start Menu.

You can now Right Click any other Chrome shortcuts/applications from the Desktop and try running it.

If you are trying to update Chrome, first remove the old one, then install it from the official Google website.

What site are you downloading Chrome from ? Is this the first time you have downloaded Chrome ?

Is Chrome listed in your installed programs in the Control Panel ? If so uninstall, and try again......or

What version of Chrome ?

When it takes you to the Google search page, is the Chrome wrench icon in the right corner of your screen ? If so, click the wrench icon, go to options, and set up your home page.

It was already downloaded I think, I don't remember because it has been on there a while. Yes Chrome is listed in my installed programs I do have the wrench in the corner.
Now I just wanted to use chrome for a while to see how it compared with firefox which I have used for years. I don't want to screw anything up by going to chrome

Best to uninstall from programs, go to the Google site and download the most recent version.

Now will my bookmarks from firefox be on chrome and I still would like to know if I am going to louse up my computer by doing this?

No, you will have to import the bookmarks to Chrome from Firefox. You stated you wanted to compare Chrome. Uninstall the old version, download the most recent. If you like, then you can import bookmarks, etc. Should not effect your computer, however, most people do not have 3 browsers downloaded.