Virus infecting microsoft programs

Its the W32/Rungbu-A virus, it infects Microsoft Word DOC files by copying itself to the same filename but with an .SCR extension, appending the DOC file to the SCR copy, and then hiding the original DOC file.

The W32/Rungbu-A then sets the computer not to show hidden files (in order to hide the DOC file), to give SCR files a Word icon (so the SCR file looks like a Word file), and to hide file extensions (so the SCR file just displays the filename, not the SCR extension). When the SCR file is run, the Word document is displayed as normal.

To recover your .DOC files just follow these steps:

You have to delete all files detected as W32/Rungbu-A.

Set the following registry entries in order to show extensions and hidden files:

HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
HideFileExt
0

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\HideFileExt
UncheckedValue
0

HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
ShowSuperHidden
1

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\SuperHidden
UncheckedValue
1

You must change the attributes of the original .DOC files to stop them being hidden.

My answer to your second question, is in November of 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.

the laptop is infected by a trojan.it genarally comes when you download screensaver online.install a good antivirus like latest version macafee.the AVG free edition also a good one.

It does not sound like a Virus.
Is she able to Open her docs. using another extension.
If she has a antivirus prog. update prog. Disconnect from Internet,disable System Restore,run virus scan.
Delete any viruses found.
Reboot
Enable System Restore.
lets know how you went.