I'm working on a Windows XP Pro computer that was badly infected. The infections were removed by connecting the hard drive to another computer and running virus removal tools there. But when the hard drive is installed and booted from, the operating system is currently not able to run any programs.
For example: Clicking on Start -> Run, typing in "cmd" or "regedit" or any other diagnostic program, then pressing the return key, an operating system popup is displayed which presents a list of available known programs that can be chosen to open this file type.
I've researched this problem and found a couple of good suggestions, like this one:
In a nutshell, there are a series of registry editing commands to be put into a file with a .reg extension. Double clicking on the file will display a warning prompt that "Are you sure you want to add the information in: ... to the registry?", Yes, "Information ... has been successfully added into the registry.". There is no change in running programs immediately after this, or after rebooting.
Note that the System Restore cannot be used, because the same "Open With" dialog box is displayed, asking which program to use to open this file.
Are there any recommendations on how else to solve this problem, or perhaps to learn more about it?