have you downloaded some screensavers? they can be infected sometimes.

files with the extension .scr is screensavers i think.

here is some information to you about the .scr extension:

In November 2007 the SCR file extension started to be used to transmit a Trojan. As a script or a screen saver this file can execute other files which carry the Trojan. The SCR file may be embedded within a ZIP file which could also contain a file with a double extension.

Many Windows screen savers come with a .SCR extension by default. Usually these will be found in the Windows main directory. Use caution if you receive a screen saver file via E-mail. These files can contain executable code and can be worms or viruses. Note: This file type can become infected and should be carefully scanned if someone sends you a file with this extension.

maybe you want to ask for help in the malware removal forums http://forums.spybot.info/forumdisplay.php?f=22