Pocket PCs have very small hard drives as a result of their minute size. When you have too much information on the hard drive, the Pocket PC could run very slowly. Instead of storing information on your Pocket PC's hard drive, buy an external hard drive and store all the nonprogram files there. Formatting an overloaded pocket PC can speed it up greatly. Also, formatting a pocket PC will remove any viruses that are on your computer. Formatting removes all the files in your computer except the operating system.