I having a problem whereby my hardisk capacity is 250Gige but when I installed on my PC it only shown 147Gige?

How old is your computer? What operating system are you using? If you are using anything older than XP, your operating system is unable to recognize that whole drive. If your using XP, there are somethings you have to look out for. If your computer is more than 4-5 years old, your XP disc that you used to restore the machine is probably at fault. If your XP disc is pre- service pack 1, there is your problem. Before service pack one - the maximum size of hard drive that XP could recognize was - you guessed it - 147GB. Reload windows using an XP SP2 disc, it will be able to read the whole drive.