Safe mode helps you diagnose problems. For example, if you cannot access the internet and cannot find out the reason, you can restart your computer, press F8 and then choose Safe Mode with Networking option. If you can access internet in safe mode, it means some startup items or services disable your network connection. Now you can run the command 'TaskList >d:\Anquan.txt' to record all the current processes into Anquan.txt at D drive. Restart your computer and enter the normal mode, and compare all the processes with those in Anquan.txt. You will find much more processes in normal mode. Now you can one by one stop those processes, which are not listed in Anquan.txt. If your network connection can work after you stop a process, that means this process cause the problem.

Sometimes antivirus software can detect a virus but cannot clean or delete it. In this case you can always try to enter safe mode, run antivirus software and try to clean or delete it.

More about Windows Safe mode please visit http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/boot_failsafe.mspx?mfr=true