Is Linux harder to learn than Windows? / Is Linux user-friendly?
Linux is a powerful and sophisticated operating system. If you just want to copy some files and watch movies (the latest versions are much better - KDE 3.01 and Gnome 2.0 as of this writing), then things would probably be at least as easy as Windows. Of course there are differences in the way files are displayed and some minor annoyances with the interface, and you have to be aware of that. However if you want to learn the internal details or improve the performance the system then the command line (terminal or shell) would be the only way out. People with some UNIX background would probably find everything similar. If you weren't that lucky then you would find the commands to be similar to DOS. The command line is far more powerful and is capable of achieving things you can't even dream up with a graphical interface. I would suggest that you stick with the graphical interface and try the command line later when you start feeling comfortable with the system. Dont let fear get into your way of exploring things. As a precautionary measure, backup critical files before changing them.
My favourite software/hardware doesn't work in Linux. What do I do?
Make sure there isn't a Linux version of your software. If it's a really famous application then there may be similar clones. Contact the software developer to ask whether something will be developed soon. If not, I am sorry, I can't help but just email me and I will try to let you know what I can find. If it's hardware, then try going to the hardware manufacturer's site to search for a Linux driver. Some manufacturers have started to support Linux. There may be unofficial versions too. Try using a search engine like http://www.google.com/linux for the latest drivers. If your hardware is very new there may not be anything available in Linux and you may need to wait for things to settle a bit before you start inquiring. Newer kernels usually support more devices. If your hardware isn't supported by the manufacturer or anybody else then there is probably not much that you can do other than bugging your manufacturer or writing your own device driver (though I wouldn't consider that an option for most of the users out there).
Is Linux virus-free?
No. Linux by itself is not immune to viruses, worms or Trojan horses but it uses a strict security system which reduces the effect of viruses unless you are running the system as a root user (which is never recommended). Linux viruses are very few, and in general you can be relatively sure that a virus won't attack your system. You don't need to use antivirus software. This may change in the near future when Linux becomes more popular, so you should be aware of the security and other related stuff anyway.
Is Linux stable?
Yes, but not crash proof. Linux machines are usually used more as servers than as desktop operating systems. It is known to be more stable than Windows. Instability is probably not much more than an irritation for desktop users, but can mean loss of productivity, money or even life for mission critical usage to others. Linux is often used for Web-servers or file-servers. The uptime (the amount of time after the last reboot) of these systems is usually in months or even years, and that by itself testifies the stability of Linux systems. It usually has fewer bugs than Windows. Even if an application crashes in Linux it probably won't bring the whole system down, unlike Windows.
Is Linux secure?
Yes. It has fewer security related bugs than Windows. For reasons similar to what's stated in the previous answer, we need to have a secure system for servers. Linux was designed with security in mind ever since development started, so you can be pretty sure of the security under Linux. However you should be aware that no operating system is 100% bug free or foolproof. If you are a system administrator you need to keep track of the security related issues through administrator's magazines, websites and newsletters.
I know that Linux is free. Why should I pay to for it?
Linux is available for free on the Internet and in computer magazine CDs. It is also usually legal to borrow a Linux CD from your friend for installation, but you need to spend money to buy Linux distributions like RedHat or Caldera. This makes sense because you get a huge collection of software that is bundled and extensively tested by these companies before distributing in CDs or over the Internet. You also usually get printed manuals, service and support from these companies (not available for free). You choose what you want. If you are new to Linux without any friends around who has used used Linux,I would suggest getting a paid version.
I am using my Linux system at home. Why can't I run the system as a root user?
No. Don't ever do it. Even when you are the only person using the Linux system it is always better to create another normal user with restricted rights. This is because the root user is an all-powerful person and the chances of him/her damaging a critical file or doing anything similar accidentally is very high (believe me, guys!!). Any mischievious program like a virus or trojan horse would not have any access to files that you do not, which ensures that the effect of the program would be minimal if any. Morever a cracker who manages to access your system through a network or the Internet would not be able to play with critical files. Unless you are installing software or doing anything else that requires you to be a root user don't do it. Even then its better to use the su(super user) command to do the task instead of logging in as root user.
How do I maintain my Linux system?
You may have got used to running programs like Scandisk and performing disk defragmentation periodically with your Windows system. Linux native file systems (usually ext2/ext3) have been designed to reduce fragmentation. That means that you don't need to worry about the files getting fragmented in your Linux system. There are defragmentation utilities for Linux but they are not meant for casual usage unlike Disk defragmenter. Just like newer versions of Windows, which forces scandisk to run everytime the system is not shutdown properly, Linux uses a program called fsck (file system check) which you may or may not have the option to cancel during system startup (that depends on your Linux distribution). RedHat version 7.2 and above ask your confirmation before running fsck. You do not need to run any antivirus software at all. So the amount of time you spend for maintenance is significantly less.
Why don't many Linux files have extensions?
The simple answer is that they are not really needed. In Windows, file types are identified by their extensions (for example .exe for executables and .doc for Word Documents). In Linux file types are usually identified with a unique identity called the magic number. We may also use file extensions. In Linux executable files are identified by a special flag, which is set for each and every file. In the command line, the ls command usually displays these files by a different colour. Under KDE or gnome use the file properties to identify the file type.
Why do we need both KDE and Gnome?
We don't. They are just alternative graphical interfaces. You can use any one of them of your choice. A KDE application can be used in Gnome or vice versa, with just a few basic files installed. Gnome development started after KDE for historic reasons. They both offer many similar features and competition is good for the end user (you). You can choose to run either of them as you wish.
I don't want to use Linux. How do I remove it?
Pretty easy. You have to perform two steps.
Boot up in DOS using a boot disk/Startup disk (not the MS-DOS prompt/Command line provided by Windows) and then remove the Linux partitions using fdisk.(they are indicated as NON-DOS partitions).Re-create new partitions to fill up the free space.
Run the fdisk/mbr command to remove the boot-up options.
You may also change the filesystem type or remove the partitions using Linux fdisk but this is probably the easiest way.