Will not boot up

Hi. This situation is caused by one or more of 3 possible problems. In most cases, this long 5 second error you describe is a result of faulty RAM memory, despite what you say. The reason i say this is because every computer runs a diagnostic test on all its hardware, shortly before it starts to load Windows, to make sure everything works properly. When it finds a problem, it just stops, thereby protecting the integrity of your Windows installation. You seem confident enough to try to fix the problem yourself, but be careful. You run the risk of damaging your hard drive every time you turn the computer on, but even if you find and resolve this particular problem, your computer may still refuse to boot up, if the boot sector becomes corrupted. Assuming you're using Windows XP, you don't have enough RAM anyway, as Windows XP needs at least 512 MB to work efficiently. The reason your computer only had 256 MB when you bought it, is because some manufacturers often put the bare minimum in a computer, to keep the price low. This is ok on a brand new system, with no software installed, but as soon as you start installing programs, and especially if you use the internet as well, you MUST increase the computer's RAM, to compensate for the extra workload. NOT doing this, forces the computer to compromise its resources, and this means that all the components will struggle to cope. The other possibility is that the graphics card has broken down. The first thing to do, is to remove the 256 MB memory stick, and take it to your local Computer Exchange shop, and buy 2 used memory sticks of the exact same type. The memory stick will have a white label with number codes on it, so just ask for 2 more of the EXACT same type. After you fit these, if your computer still won't start, at least you won't have wasted £30 or £40 by buying it new, but if that doesn't solve the problem, you'll still need the RAM anyway, after it's been fixed. The easiest and safest option, is to take the main tower to your nearest computer repair shop, and pay them to fix it. NEVER tell a computer repair shop that you tried to fix it yourself, as a few shops will use it as a reason to charge you more money. The worst case scenario is a faulty Motherboard, but this is very rare. Am sorry that this explanation is so long, but i hope it helps you.

The main board is telling you that a component is not functioning. Most of the times its the display adapter, if you don't have a display adapt or remove the ram and re insert to make a good contact. If you do have a display adapter remove it and plug into the on board display to see if on, or just remove and reinsert it maybe its only a contact problem. PLease remove the power Cable when you do this to prevent damage.