Before doing any work on your PC, its very important to ensure there are no hardware problems with your PC. Many problems, such as random blue screens (your PC randomly rebooting, going to a blue screen with a bunch of white text, or randomly powering down), and major slowdowns are frequently caused by failing components. Most likely the failing component is either a memory stick or a hard drive.

The following is a step-by-step tutorial on how to run full hardware diagnostics on your computer with free tools used by professionals:

1. First of all, be sure to backup all of your data. This step is very important because if you have a failing hard drive, running the diagnostics will put a large amount of strain on your PC’s components and may very well cause the drive to completely fail. Click here for instructions on doing this.

2. Download both memtest86 and Drive Fitness Test (DFT). If you have CD burning software (Nero, Roxio, Sonic, etc.) you can simply click the ISO of the DFT file you downloaded, insert a blank disc and click burn. For memtest, you will need to double click the ZIP file, then double click the ISO file within the ZIP file. If you are prompted to choose Run or Extract All, choose Run.

3. If you do not have any CD burning software, I reccomend downloading ImgBurn, a free application that will let you burn these images. Install the application, then repeat step 2 to burn both DFT and memtest to CD-R discs.

4. Insert the memtest CD into your PC and reboot. Most PCs will automatically boot from the CD. If the PC boots back into windows, reboot again. When the manufacturer’s logo appears, look for options such as “Boot Menu” and start tapping the key it shows. On most Dell PCs, this is the F12 key (stop tapping once the computer beeps, or it will throw a keyboard error), on most HPs its the ESC key. Some ASUS boards also use the F8 key, and some others use th F10 key. Be careful, though, F10 is usually the Recovery partition on HPs, and for some reason, the Boot Menu on other models. Choose the CD/DVD drive from the list and hit enter.

5. Memtest wil begin testing your RAM. This may take anywhere from 10 minutes to 3-4 hours, depening on the amount of RAM, the chipset on your motherboard, and the speed of the RAM. If the test passes without error, you will be shown the following screen. If problems are found, the specific addresses of the errors will show up underneath the time.

6. If problems are found, turn off the PC, unplug it, open it up and pull all but one of the RAM sticks. Repeat step 4 above with each individual stick of RAM until you find the bad stick. If you only have one RAM stick, it is most likely bad and must be replaced. If all RAM sticks are failing, or if you only have one stick that has failed, be sure to re-run the tests in another RAM slot. Sometimes the RAM slot or Memory controller fails and one slot “dies.” If the RAM passes in the other slot, most likely you have a failing motherboard and/or CPU, and it is reccomended that you replace the computer.

7. Now, remove the memtest disc, insert the DFT disc and reboot (if memtest is running, simply press the ESC key to reboot). Follow the same steps as in step 4 to boot from the CD. Choose “ATA Support Only” from the menu:

At the main menu, choose your hard drive, then choose Advanced Test. Choose start, then let it go. This may take anywhere from a few seconds (if the drive is very bad), to 2 hours to run.

If you get a Green Screen at the end like the one below, the drive has passed. If you get a Red Screen, the drive is bad and needs to be replaced. If you receive a Corrupt Sectors red screen, the drive can sometimes be repaired, but it is reccomended that it be replacecd as its most likely failing. DFT does have some glitches though. Many newer Serial ATA controllers are not supported and RAID arrays found in some newer computers are not supported. On some PCs, a red bar will appear at the bottom of the screen telling you that the media check failed. This is referring to the floppy drive. Simply press ESC to see the results of the Hard Drive test.

8. If both diagnostics pass, congratulations, your computer is physically in good working condition. Otherwise, replace the failing component(s) and then continue on. A replacement Hard Drive will need a reinstallation of Windows, and a replacement RAM stick might if the machine fails to boot or runs improperly even after the RAM has been replaced.