The speed and capability of a computer is decided by four factors: the processor, RAM, video card and primary hard disk. While each individual piece governs the speed of certain computer tasks, typically computers use multiple parts at the same time.
When determining how to speed up a computer, it is important to understand the primary use of the computer. For Internet surfing and general computer use, an average processor and RAM suffices. For video and photo editing or high-end gaming, not only are a better processor and RAM important, but a powerful video card is needed. Having one or two fast components while skimping on the others causes the speed of the computer to bottleneck, meaning the computer can only be as fast as its slowest component.