Windows is simple enough that I was able to teach a COMPLETE NEWBIE the basics in less than two hours. Then again, any OS is simple if you have the right teacher.
I can't say too much about Mac OS X and Linux without being too biased, as I didn't keep using them for long, but I can give some upsides and downsides for Windows XP.
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Windows XP upsides:
Has thousands, if not millions, of programs that you can choose from. You can find software almost anywhere on the net or in stores
Driver support is usually no problem
Is really needed if you plan on mainly gaming
Windows XP downsides:
Isn't as secure as Windows 9x, Mac OS X, or Linux
No real person to person customer support
Is more prone to crashing compared to Mac and Linux
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I can say that, in my personal opinion, Windows has always given me the best time. I've never found either of the other two as user friendly as Windows. Sure, it crashes some, but it's always something I did, like forgetting to install a virus scanner FIRST. X_x;
Here's a suggestion, though. Try and find a store with each OS. If nobody has a Linux box, and you have a CD-R or RW and access to a CD-R or CD-RW drive, and a computer that they'll allow you to do this on, then here's what you do:
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1) Head to
https://kanotix.com/info/index.php and go to the downloads area. Download the first .iso file on the list. It'll take a while, as it's about 700 MB.
2) Get a CD image burning program. I suggest
BurnCDCC. It's free and lightweight.
3) Use the program to burn the .iso file to the disk. Don't unzip it or anything, as that won't do anything.
4) When it's done, reboot the machine with the CD in the drive. It'll boot as the Linux distro "Kanotix", all from the CD. It won't install anything. Instead, it's all done ON THE CD!
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While you can't really download and install anything while using a live-cd, it allows you to use the interface, use the base programs, and even get used to the terminal and such. It's also useful as a rescue disk when running Windows.
In the end, I can only suggest Windows as it's what I've found to be the most useful, but I'd suggest trying the different OS systems yourself instead of relying on others to make your desicion. If you choose Windows, we'd be glad to help get you set up with some good software to try and keep you secure. Same goes with any other OS you choose.
Also, remember that any OS can give you a hard time if you let it. Learn as much as you can about whatever OS you choose. An OS is only as smart, user-friendly and secure and the user let's it be.