If you can get into safe mode you may be able to install and run something, but if the machine reboots when you boot into safe mode as well, then you’ll probably need to format and reinstall Windows.
Without being able to log into the system you aren’t going to be able to do much, as you need to be logged into the system to install and run most anti-virus / anti-spyware software.
What software are you trying to use to clean the server?
*** Improved by Wrobinson on 02/08/08 ***
Mrdenny is right, you need to be able to boot into safe mode at a minimum to clean the OS; however, you may still be able to do so by booting into Windows PE but that increases the level of complexity of the effort considerably.
Here are some tools and utilities that you can use:
Malware detection and removal tools
Malware detection and removal software:
Free online anti-virus and malware scans:
General computer security recommendations from Microsoft:
If the system is rebooting you can cancel it if you have some fast fingers. when you login try to open a command prompt and type shutdown -a and hit enter.
shutdown -a is a shutdown abort command. if you can get it in fast enough you can cancel the shutdown. also as soon as you stop the shutdown create a batch file on the desktop that has that command in it. that way if it comes up again you can double click on it fast and stop the shutdown. this will give you time to try to clean it.
another thing you could do is create the batch file on another file server. then create a shortcut to it and put it on the desktop of the profile for the account that you login as. that way the shortcut will be there as soon as you login.
Most spyware programs are really so clever where they have the ability to edit or hide itself effectively. The most important thing you have to do is to purchase and installe the latest and updated antivirus software and perform a full system scan.
There are quite a few offline malware/rootkit scanners in the form of bootdisks. These scanners boot their own OS leaving Windows out of the the picture. With Windows not running, the malware can’t activate and the offline scanner will find and remove the malware files and registry traces. Here are some links to tools that I use frequently: