For personal use
Before you buy a computer, you should first decide where you will be using the computer—for personal use or business. Since most people treat the two uses as the same and often buy a fully loaded computer for personal use. For instance, they will get massive hard drive and RAM (Random-Access Memory), which will not do any good except they waste their money and the extra disk space on their computer. Unless you have a specific task that requires big hard drive and RAM, do not waste your money. You should also decide which one will be best—a desktop or a laptop.
For business use
If you want to buy a computer for business use, get a detailed quote from a dealer. Since your final decision will depend on what system works best for your business needs, a desktop or a laptop, you have a wide variety of features at your disposal.
How fast it should be?
You have many when it comes to speed and power. You definitely want a product that is fast and nimble, regardless of the use (business or personal). If it is slower than at least 1GHz, it is nothing new. So, if you want speed, it should not be less than 1GHz. For heavy software, which require huge RAM and processor, you are advised to get a 3.3GHZ processor.
If your job is to keep records or you work on graphics designing, you need a bigger hard drive. Ask your computer dealer for the largest hard disk.
Desktop or laptop
If want to use computer for long hours such as gaming, graphics designing, or writing, a desktop will be suitable. However, for a more hassle-free use, a laptop will be best as it is easy to carry and maintain.