If your computer is a member of an Active Directory domain contact an
administrator. If not and you are using XP Pro try running rsop.msc on it to
see if you can find any Group Policy settings in local Group Policy that may
be denying access. You can use gpedit.msc to manage local Group Policy. If
none of that is the case most likely your computer has a bad problem with
malware and you should proceed accordingly including scanning in Safe Mode
for malware and spyware being sure to use the latest definitions for
whatever program you scan with. Cleaning detected malware/spyware may not
however restore your access as many registry settings restricting users are
not changed. Another option is to try System Restore if you have a restore
point before all your problems began though doing that will not remove
malware and spyware and could reinfect a cleaned computer. --- Steve
http://www.microsoft.com/athome/security/protect/windowsxpsp2/Default.mspx
--- Protect Your PC tips and links on how to deal with malware and spyware.
http://www.microsoft.com/windowsxp/using/helpandsupport/getstarted/ballew_03may19.mspx
-- XP System Restore
