How do I remove the fbi virus from firefox ?

I have installed malware software, even there is a QUICK HEAL ANTI SOFTWARE installed in my computer. System got stuck and applications are running slowly due to virus problem, I want to remove virus and wants to improve system performance. I want to know how to fragment(don't know) the system or reboot. :confused:

Here is what you need to do

1. Reboot your computer in Safe Mode with Networking by pressing F8 (or F5 on some computers) before Windows starts (before the Windows logo appears) and choosing Safe Mode with Networking from the following screen.

2. Download the Combofix tool from here.
Note: Do not mouse click ComboFix's window while it is running. That may cause it to stall.
When finished, it will produce a log for you. The log is automatically saved on C:\ and is named Combofix.txt.

3. Restart in Normal Mode and attach the log to your reply.

Thank you for reply. I will follow your instruction in future if , the problem which I was facing was resolved by some one else.
But still now I wan't to be remain in this forum .So that I can possibly suggest some rescues to other users who suffer from same issues which I use to have. I am from California, I use to travel for my business purpose, and use to face lots of issues on my laptop.