Important thing to note when switching from WINDOWS to UBUNTU..

Recently UBUNTU has gained much popularity among college students and others than the past... Many are willing to try UBUNTU who had been get used to with WINDOWS. Actually I am such a person, and took some time to get tuned with UBUNTU... So this post is for all migrators to UBUNTU from WINDOWS .
    Just keep in mind some things and U will find Ubuntu lot more interesting..

.EXE Files in windows and packages in UBUNTU
                   Windows software comes in .exe files, which you are expected to get from the web or from a store. Ubuntu software comes in packages, which are installed and updated through a centralised system, like a more powerful version of Windows Update and Add/Remove Programs. Application packages will usually appear in the Applicationsmenu, configuration tools will usually appear in the Preferences orAdministration menu.In the same way that Windows only runs software designed for Windows, applications must be made for Linux to be able to run on Ubuntu. Most Linux software is available for free over the Internet.

Firewalls and antivirus software

Ubuntu's main firewall program is called ufw (click here to install gufw). There are currently very few Linux viruses in the wild, so Ubuntu doesn't come with antivirus software installed.

The Terminal

Linux includes a text-based interface like cmd.exe, called the terminal. Many Linux guides ask you to run commands in the terminal, which should be available from Applications > Accessories > Terminal. 

Task Manager

Ubuntu's System Monitor is the closest equivalent to the Task Manager in Windows. It's available through System > Administration > System Monitor.

Where To Put Your Files

Linux doesn't use drive letters, so there's no C: drive and no D: drive. You'll get used to Linux's filesystem gradually, but for now here are the most important locations:

/home/

This is your home folder, which is fairly similar to My Documents in Windows. You can access this folder by clicking Places> Home Folder. Because this folder is used so often, many programs refer to it as "$HOME" or "~" ("tilde", pronounced "till-der". For example, saving a file as ~/my-file.txt is the same as saving it as /home//my-file.txt

/home

This is folder contains everybody's home folders, and is fairly similar to Documents and Settings in Windows. The main thing to remember is that despite the name, this is not your home folder. If somebody tells you to go to your home folder, they mean /home/.

/media

This folder contains CD-ROMs, memory sticks, and other removable media. Individual drives will also appear in the Places menu item and on your desktop.

/tmp

This folder contains temporary files, and is cleaned out when you reboot.

Safely removing drives

When you are finished with a removable drive, right click on the drive's desktop icon and select Unmount volume or Eject, depending on what type of drive it is.

Dual-Boot

When you are looking to switch to Ubuntu one option that may make the transition a little easier is setting up a dual-boot. In a dual-boot, during the boot process, a menu will appear, allowing you to choose from one of two OS's. This allows you to try out Ubuntu while keeping your Windows installation.

Traditional

In a traditional dual-boot Windows will be installed along side of Ubuntu each having it's own partition. If Windows is already installed, this option does pose some risk. To enable each OS to have it's own partition you will need to edit the partition which has the risk of data loss.

Wubi

If you are not ready for this, another option would be Wubi. Wubi is a special installation that will install Ubuntu within Windows similar to any other program. When installing Wubi, you specify how much of the hard drive to devote to Wubi. Not changing the partitions removes the risk of data loss.

                                                                                        SOURCE : www.help.ubuntu.com