Problem #1: Computer Does Not Start at All
If your computer does not get powered up at all, then the problem is very obvious. It has something to do with the power supply system of your computer.
This is one of the procedures to troubleshoot computer hardware problems that can either be very simple or can go way beyond your capability to solve. The solution may be as simple as replacing the power cable with a new one or as complicated as dealing with the SMPS of the computer system. The SMPS is the Switched Mode Power Supply, the box at the upper left hand corner of your CPU, which powers up each and every component in your computer. If the problem lies with the SMPS, then solving it is not one of the DIY tasks that you would like to take up at home. It will need good technical expertise to solve the problem. Many a times, the problem may have just one solution, that is, replacing your computer's SMPS.
Problem #2: Computer Freezes or Shuts Down Suddenly
If you are facing the problem that your operating system stops responding suddenly or the computer shuts down itself, then there may be some hardware related issue out here. Before I start off with the computer hardware troubleshooting tips for this problem, I should tell you that most of the times, these are problems related to some software running in your system or because of some wrong driver installation. However, assuming that you have already checked out these problems and are sure that the problem is not related to the software of the computer, lets start off with the computer hardware troubleshooting part.
Most of the times, this is a problem related to heat issues. If your computer processor gets heated up then there is a chance that your computer may shut down. The probable cause for this problem is that the fan in your CPU is not working properly. Here, I am assuming that you are using a desktop computer as troubleshooting a laptop computer, would of course require a lot of expertise. You can make out whether the fan is rotating properly, by simply observing it at the back of your CPU. There are also certain on screen system programs which can show whether your computer processor is over heated or not. If your fan is not rotating smoothly, then you have to get the connections to your fan checked. Another step that you can take is that you need to observe if the BIOS can properly load the fan when starting off the computer. However, if you find out that your computer fan is working properly, then you should take into consideration any new hardware that you had added to the system. Try removing that and check out if the computer restores back to working properly. There are chances that this hardware may be faulty. Replace a new hardware with this. Again, if you have not added a new computer hardware to your system in recent times, then the reason may be some computer hardware part that is already there in your computer. Open your CPU cabinet and remove any extra RAM or extra hard disk that you are using. Check out if your computer works properly without that particular component. You can also try disconnecting your MODEM to check if the computer works properly.
Problem #3: Computer Boots Up Only from Floppy Drive
If on starting up your system, you system demands to insert a floppy disk to install the system, then probably there is some problem with the hard drive of the system.
Before going into the troubleshooting part and considering the hard disk to be corrupt, figure out in the BIOS settings if your hard disk has been given the first priority for booting up. If it has not been given the first priority, then change the priority level and put your hard disk at the first priority level. If this does not help, then probably your computer hard disk is corrupt. In that case, if you have a recovery or backup system in your computer, then use it for recovering the data and the operating system. The other possible solution is that you need to reformat your hard disk. If you want to learn reformatting a hard drive, then you can refer to the article, how to reformat a hard drive.
The computer hardware troubleshooting tips that I have provided in this article are for the most common computer hardware problems that you may face. To have a deeper understanding on how to go ahead with the computer hardware repair of even the most complicated problems, you need to get into the details of the working of that particular hardware device. For more on computer hardware troubleshooting, please read the articles, Computer Hardware Repair and Maintenance and Hardware Repair: Computer Hardware Troubleshooting Tips and Tools