Windows Xp logon virus.Please help!

Hello,
Yesterday I was cleaning my computer and found a folder with an application. Stupid enough I click on it.My antivirus was active but it didnt help me because then it started:I was kicked out of windows desktop to windows logon page where my user account (only one on this computer) is asking for a password which was never set.
What I ve tried since is this:

http://pubs.logicalexpressions.com/pub0009/LPMArticle.asp?ID=305
everything went ok just to the point where I have graphical access to my user accounts but message say it cant find user accounts and I should reboot and try it again.Which I did and had the same result.
Then I was at least able to run safe mode(I had blue error message screen before reinstaling xp) but again I can only get to the windows logon screen.But as well as my user account there is also administrator account asking for pw too.
When I tried to run system restore I end up at the point where I?m asked for that administrator password.
Since yesterday a read lot of stuff but nothing what really works.
Please help me to save my data!!!
I got Win Xp installatin Cd is there any help for me???