Windows XP Computer infected badly - Help Please!

[JBGator]

I am new to this site but have read various threads to get a general understanding of some content. I am not sure if I am posting in the right place and doing the right thing, and if I am not, I apologize. My son's computer is infected with a serious malware problem. Having read other threads, I have downlaoded HijackThis and Antil-Malware, yet the malware has so gripped his computer that I cannot even install it or access it from a usb port or cd drive. I have been unable to boot up with a boot disk and even in safe mode I cannot get to system restore. I have no idea how to attach this problem. I have tried everything. The Malware is a popup saying Windows has been infected and I need to purchase anti-virus softeare. It, of course directs me to a website that wants a credit card number to purchase anti-spyware information. Any help would be greatly welcomed.
Thank you in advance.
JB

[NonSuch]

We understand that you are having difficulty running certain programs, including HijackThis. However, in order for us to help you it is necessary that you provide us with a HijackThis log, and it is possible you may be able to trick the malware into letting you do this. First, download HijackThis to a clean computer, then rename it from HijackThis.exe to any other name you want, using an .exe extension, for example... YourLastName.exe. Once you have done that, burn it to a CD (preferable to using a flash drive that may easily become infected) then transfer the renamed file to the infected computer and run a scan, then start a new topic and include your HijackThis log.

Please follow the guideline at the link below to start a new topic and post your HijackThis log. If you are unable to create and post a HijackThis log, then your only option may be to reformat your computer and reinstall the operating system.

This topic is now closed. Please start a new topic by following the HijackThis Guideline posted here, just be certain to rename HijackThis: >Guideline for posting your HijackThis log<