When downloading HP software I was instructed to disable the programmes on the start up menue. Now I can not restore them Windows XP keeps telling me it has to be done by an administrator but I am theonly person who uses the PC and am shown as heving administartors rights.
You have administrator rights but you aren't the System Administrator. To find that account in XP, restart and tap Function 8 as it begins to load Windows then choose Safe Mode from the menu and click the Administrator login in logo.
Having fallen for HP's con-trick, you may need System Restore to undo any damage their software may have done. As a general rule, any programme that tells you to disable any other - particularly your AV or firewall - is not worth installing.