Where cookies are stored in system?

IE and Windows keeps cookies here:

%AppData%\Microsoft\Windows\Cookies

Points to the same directory as @Sohnee's does under Windows Visa and newer, but his doesn't under Windows XP and earlier, my - does.

also Temporary Internet Files can contain some cookies.

Meanwhile Firefox keeps cookies into SQLite database under profile root:

%AppData%\Mozilla\Firefox\Profiles\%FirefoxProfile%\cookies.sqlite

To read the data you need to connect to that database using any SQLite client and execute next query:

select value
from moz_cookies
where name = 'test'

I did it just now using trial SQLite Maestro. And don't forget to close all running Firefoxes before connection attempt.

Cookies are stored in the cookies folder on Windows 7. To open the cookies folder, open run in Windows and type shell:cookies. Also, as suggested above, they might be in Temporary internet files. However, I see that your cookies are not persistent. This means you are not setting any expiration on them. Therefore, they won't be stored on your machine and they will only be part of the browser's memory.

C:\Users\<user_name>\AppData\Local\Google\Chrome\User Data\Default

Also note, "Local" is a hidden folder.