Computer appears in the title of the problem, click on the properties of My Computer pop-up a dialog box said "Can't find C:windowssystem32undll32.exe", and later want to open some installed software program but pop-up a will you choose to open the way of the dialog box, Later discovered that the anti-virus software also disappeared, even more surprised me is incredibly cannot install the file!
Workaround: The exe open method is modified by Trojans or viruses, unable to open any executable file solution.
Option one: First change the name of Regedit.exe to Regedit.com or REGEDIT.SCR.
Run regedit.com, locate the Hkey_classes_rootexefileshellopencommand key value, change the default value to%1%* reboot, and then change regedit.com back to Regedit.exe.
Scenario Two: Save the following content as Exefile.reg, double-click the Import registry, or run Regedit exefile.reg in pure DOS, import the registry. (Note: Leave a blank line behind the REGEDIT4)
Regedit4
[Hkey_classes_rootexefileshellopencommand]
@=\%1%*
Programme III (applicable to WIN2000/XP only):
1, will cmd.exe renamed as Cmd.com or CMD.SCR.
2. Operation Cmd.com
3, run the following two commands: Ftype exefile=%1%*assoc. exe=exefile
4. Change the cmd.com back to Cmd.exe
Scheme four: The new association EXE file. Open any window (other than IE window), Tools---Folder Options----file type----new ———— fill in "EXE" in "File extension"-----Click Advanced and select "Application" in the Pull-down menu-------OK.