Some Advice for Beginners

Your computer should not be more than five years old.
The Operating System software and Anti Virus software should be up to date.
A permanent internet connection. (Dial-up connections are not recommended).
Choose a good reputable online poker room.
Download and install the software.
Sign-up giving your correct details. This is important if you ever wish to withdraw your winnings and also for depositing real money.
You can only create one account with a particular poker room, so do it right first time.
You must never have two accounts, for the same poker room, (you or a friend) running off the same computer. You will be banned.
Play for free first to get comfortable with the software and with the game itself.
Only progress to real money play when you feel confident enough to do so.