First more info is needed. Have you determined if you are logged on as an
administrator or not?? What operating system - XP Home or XP Pro?. If it
you are indeed logged on as an administrator in XP Home and you have access
denied to a service your repair options are limited and you may need to do a
repair install. With XP Pro you could try using secedit to restore security
settings to default defined levels as shown in the article below. In either
case being denied access to a service as an administrator could indicate a
problem with malware or spyware unless you have used a protection program to
lock down your computer which many can do such as SpyBot Search and Destroy
if you enable that option. -- Steve
http://support.microsoft.com/default.aspx?scid=kb;EN-US;313222