Modern processors generate more heat and when the temperature rises above the level specified via the BIOS, it can be why your PC is slow. Cleaning your PC fan can help. You should also check the fan motor to see if any bearings are loose. Setting the BIOS temperature level to a slightly higher figure than the current one can help when your PC is slow.
Malfunctioning RAM
If the installed RAM is not compatible with your PC or is slower than the optimal level specified in the machine, that can be a reason why your PC is slow. A slow PC is also a sign of defective RAM chips, so you should just check if they are from a reliable manufacturer. An extra fan will help your RAM cool down.
Failing hard disk
Slow access times, irregular boot failures and unexplained blue screens are definite signs of hard disk failure, which can be why your PC is slow. You should run the Error Check utility and then the Disk Defragmenter provided with Windows. The Error Check utility will prompt you to try to repair faulty sectors, while the defragmenter will skip the bad sectors and organize your files appropriately.
Incompatible BIOS settings
If your computer's BIOS settings are different to the recommended optimal machine configuration, it can be the leading cause why your PC is slow. Run an online search with your motherboard name to find out what the appropriate settings are, and change them accordingly.
Unsupported new drive
If you experience difficulty with accessing a drive you installed recently and your PC is slow, check the IDE interface type on your motherboard. The solution for an incompatible hard drive is a PCI add-on card .
Multiple activated Windows Services
The Windows system does not need most of the applications that start running at start-up. But, since they are automatically enabled, it can affect the performance of your system, in turn becoming a cause for why your PC is slow. Right-click on My Computer and click on Manage, Services and Applications. You can use the Disable button to stop any services you don't need.
Full hard disk
Whenever you add, modify or delete files in a computer, the hard disk stores the file contents in an unorganized manner. If your PC is slow, then you will need to defragment the hard disk to achieve optimal performance. Defragmenting will organize all the scattered bits and pieces of memory according to relevancy, which means, the data belonging to one file will be located next to each other, rather than all over the disk.
A cluttered registry could also be the reason why your PC is slow. To avoid problems with the Windows Registry, use a registry tool, such as RegCure, to scan, repair and optimize your PC for long-term peak performance.
