There can be a few different reasons why your computer can overheat due to the fan, The fan can easily get dust caked onto it which will cause worse air circulation, and make the fan less efficient at cooling the computer down. This can be easily seen by taking off the case of the tower and looking at the fan. If this is the case, then make sure your computer is turned off, and simply just take some canned air that can be purchased from many stores, such as Best Buy, or online, and spray the fan to get the dust off of it. If this does not get the majority of the dust off then the faceplate of the fan unit may need to be taken off, and then the dust can be wiped off gently using a paper towel.
If your fan seems to be clean but your computer is still overheating, then your fan could be broken. To check this, Take the case off of your tower and turn the computer on. is the fan is not moving, then something is wrong with the fan, and most likely needs to be replaced. if this is the case, the refer to our fan replacement manuel.
A buildup of dust on parts within the computer can cause a variety of problems with your computer such as overheating, and should be dealt with as soon as possible.
If you turn on your computer on and it is not booting properly often times it is an issue of bad RAM. It is uncommon for only one out of your two sticks of RAM to be bad, but you can test them individually just incase it is actually just one stick of RAM. If it is one or both you must replace the sticks of RAM.
If your computer is not turning on at all, one of the issues it could be is that your motherboard is fried. To check this, look inside of your computer at your motherboard. Most of the times when the motherboard is fried, it will look like the motherboard has literally caught on fire. This could happen to large areas of the motherboard, or just small pieces to it, so look carefully at the entire motherboard to see if this is what has happened. If the motherboard is fried then it must be replaced.
If your processor, also known as the CPU is broken, then you will be able to physically see that it is broken. Just like the motherboard it will look like your CPU has caught on fire. if this is true then the processor needs to be replaced. Refer to the repair guide to see how to replace the Processor
If your computer has been overheating, the problem might be that your heatsink is blocked by dust. Open your case and check the heatsink to see if it is clogged up. Another problem is that the thermal paste holding the heatsink onto the CPU might have been applied incorrectly and is preventing ventilation.