Settings not Saving

Hi i just reinstalled my operating system on a dell inspiron 1150 windows xp pro and everything is fine, i did the reinstall of the chipset drivers and networking and video and all that, the computer is working fine, but when i go to personalize everything such as my home page on IE, my desktop theme, how to open folders, etc... for some reason everytime i shut the computer down and reopen it, all the settings i set are gone and its back to the start up of windows xp pro with the tour of windows and all the basic settings. how come it wont keep what i stored as mine?