Few days ago my computer stopped connecting to the internet. It was set to connect automatically right away the computer boot up but due to some reason it won’t connect at all. So I looked into the internet settings and it was changed without my concern. So this time I manually connected to the internet and opened the browser. But whatever page I try to open, it first loads for few seconds and then shows error message saying that website cannot load. Below I get an option to diagnose network connection. If I click on that, it starts diagnosing but after a minute it closes automatically. I am using a Windows XP computer. My friend then suggested installing QuickHeal antivirus. I installed it and ran a full scan on safe mode. It shows that computer is infected by a Trojan. I quarantined it and rebooted the system. Again ran the scan in normal mode but this time also it detected the same Crypt.AQLW Trojan but on different location. The problem is this malware is showing up during every reboot. How can I completely remove it without formatting my HDD?