You should probably check for multiple instances of Explorer.exe as this file name is associated with at least one malware. You can check by running StartupList found here; http://www.lurkhere.com/~nicefiles/index.html
In the generated txt you will see much data. Look for a section like this;
--------------------------------------------------
Checking for EXPLORER.EXE instances:
D:\WINNT\Explorer.exe: PRESENT!
C:\Explorer.exe: not present
D:\WINNT\Explorer\Explorer.exe: not present
D:\WINNT\System\Explorer.exe: not present
D:\WINNT\System32\Explorer.exe: not present
D:\WINNT\Command\Explorer.exe: not present
--------------------------------------------------
There should only be one. If more than one, please make sure your AV/AT definitions are updated because you will likely have a nasty. HTH
In the generated txt you will see much data. Look for a section like this;
--------------------------------------------------
Checking for EXPLORER.EXE instances:
D:\WINNT\Explorer.exe: PRESENT!
C:\Explorer.exe: not present
D:\WINNT\Explorer\Explorer.exe: not present
D:\WINNT\System\Explorer.exe: not present
D:\WINNT\System32\Explorer.exe: not present
D:\WINNT\Command\Explorer.exe: not present
--------------------------------------------------
There should only be one. If more than one, please make sure your AV/AT definitions are updated because you will likely have a nasty. HTH