malware issue - now admin pwd issue

I'm not sure if this should be posted to the malware forum or the software forum.
What started out as a malware problem has turned into an even bigger problem.

I have a laptop that was loaded with malware and specifically the 2010 Antivirus popup one.
I ran SuperAntiSpyware - it cleaned 3 items (despite the constant popups) then asked me to reboot.
After rebooting, i had the following issue - I would get to the log in screen, click the user name, it would flash the desktop background for a second, then log back out.
The same happens if I try to boot to safe mode.
I googled this, and found some instructions from Microsoft on how to fix this - (at http://support.microsoft.com/default.aspx?scid=kb;en-us;307545&sd=tech).
I had some grief with the first copying the repair/system - it said it didn't exist.
I tried to copy the old one back and now when I try to boot, I get an lsass.exe password error.
What makes things even worse is I can no longer boot to the repair console - now when I'm asked for an Administrator password (which was blank before) - and press enter - it says wrong.
If I boot to disk to reset the password (NT Password reset) - it says password is blank and can't be reset.
I'm kind of stuck....

Amber

 

If you had used this ... all would have been well by now ...
Fix Windows XP LogOn/LogOff Loop ..... thinkinginpixels

However, let's see if we can get your system back up and running again.
Let's get you started with the first task ....

Download &/or build yourself a bootable CD that also has the facility to edit the Windows registry off-line. Either of the following will be ideal and also enable you to recover your files if necessary.

Hiren's BootCD (my first preference, but could be illegal depending on your particular jurisdiction)

UBCD4Win (you need to build it using an XP installation CD)

When you have the bootable CD burned and established that you can boot from it, we can try to get your system back up and running again.
Once you are able to boot from one of the above CDs, I recommend that you back up your personal files to an external USB hard drive or CD/DVD or such like, in case we are not successful.