virus heat on my computer.....can't od anything to get it off

So I have the virus heat virus on my computer. I have been searching all over Google and Yahoo and can't seem to find a good answer. My problems seem to be more complex than the ones they tell you how to fix. My problems are as follows. My desktop background is now a message that says warning spyware threat has been detected on my PC and asks me to click this link to scan my pc for threats. It also have windows security alert pop ups all the time that say windows has detected a security attack. I am also unable to open almost any program on my computer. It gives a message that says "this file does not have a program associated with it for performing this action. create an association in the folder options control panel. i have tried putting programs on a USB drive to open spyware programs with that but it results in the same message. I can't get in the task manager to kill processes because it says the task manager has been disable by the administrator. I also can't get in regedit, cmd, or msconfig. I am able to get into some control panel things. I am also able to start in safe mode. i have two hard drives with all of my personal files on the other hard drive so i am able to reformat if needed. i would prefer not to just in case i forgot some files or something. i am able to get into all folders also. my machine runs with windows XP SP2. if you need anything else please let me know. if someone would like to try and remotely connect to work on it, my email is [xxxxxxx]. thanks