I have a problem over the past month and a half my computer will turn on and boot up perfectly fine. But after about 4 or 5 days I will go to work on the computer and it is still on but the operating system is not running. I have checked all the wires and cords inside and everything is in securely. The hard drive that I have is 4 months old and it is brand new. I will not be able to get the computer to boot up again for about 4 or 5 days. Then the same thing happens. I have had one of my friends who knows a lot about computers look at it and he cannot find anything wrong with it. Please HELP.

Bad power supply or dead BIOS battery , i think

If the computer is still running then it could be a bad connection to the LCD display or the video controller is playing up. If it is only 4 months old then i would suggest sending it back to you supplier under warrunty rather then trying to fix this problem yourself.

reseat your memory check if it will help...

your pc is going into power save and not able to come back out, you need to check the power supply, is it at or atx, and check the settings in the control panel for power, make sure it is not set to a presentation, but to a desk top, also chek the energy saving feature for the monitor, like turn off after 1 hours after no activity, set it to always on, see that will fix the problem

My systems doing something similar. It doesn't go past the initial Pentium load screen and doesn't even get to the prompt to enter bios. Could a loose component do that?