XP Guardian, Very specific Issues

[Poor Rufio]

I have two accounts for my pc which is running windows xp.
One is mine
The other is my mom

i awoke to this virus when my friend was browsing the net.
as soon as i saw "XP Guardian 2010 Unregistered" pop up, i knew that wasn't a real anti-virus i had on my computer, so i ran Antivir and Ad-Aware overnight, they found a few problems but when they performed their actions, there was no change. So i tried opening Firefox on my account to find a manual fix for this, only problem was, now none of my programs would open. The weird part is, my mom's account on the computer worked just fine except that it forgot our preferred program for the internet, so i had to change it to Firefox. It is also bringing up the HPProductAssistant, and its trying to install some hardware or something, but it keeps failing, its annoying. So i get on a site that says that i need to open command, and open notepad. In note pad i am to make a registry change, so i do as the site says, but when i open it and say yes to it asking if i want to change my registry, it says this is not a file that will work. I'm so confused guys, please help me fix my computer

[rodi]

Hello Rufio,

Why it won't work? Cold you tell us more about that error? Make sure you did all the steps correctly.

[Poor Rufio]

okay, well i used the exefix.reg file to change my registry to allow use of my exe programs and i am now currently on the infected win xp profile, on firefox THANKFULLY! however, i tried to download spyware doctor and it says in the download window that "This download has been blocked by your security zone policy" i want to make sure that the computer is completely sweeped clean. i got Spyware doctor on the other win xp profile, and the scan halted at 61% and froze, it wont progress past there. any ideas?