Can’t disable hibernation with Windows XP SP3 platform

Hello!
I would like to ask if you can help me resolve issue with my desktop problem. I just recently formatted my computer. Everything works fine only but the computer and monitor. Keeps on turning off if I am not doing anything and will stay off. I can’t bring it out from hibernate mode. Can you help me fix the problem? Can you tell me how to resolve this? Can you provide me also alternative resolution on how to keep this from happening again? Thank you very much and have a nice day!
