General Questions on Windows XP Functionalities

Good Day,
I want to know what are other possible problems about PC restart. I knew few tricks, solutions about PC restart but what if those options don't work out when I encounter the problem? At least I have backup ideas about that problem and when backing up files in Windows XP, where can I find the options?
How about sharing files? How about hiding some folder how can we do that one? This option is hard for me to work out really. Maybe you guys can help me and teach me some ideas about my concerns and you can ask me questions too and I'll be glad to help you.
Thank you.
