Change/remove buttons gone missing in add/remove programs panel

This past week has been a challenging week for me when it comes to using my computer. Last weekend my desktop got infected with a Trojan called VirtuMonde (read about it here ) and it took me almost the whole weekend to finally get rid of it. And then today I discovered how my laptop's Windows XP registry got messed up for some unknown reason. That took me another hour or so to get it fixed. And it was only made possible by a stroke of luck. I'll explain as we go along.

It all began when I wanted to remove/uninstall a certain program from my laptop. The usual thing to do would be to go to the Control Panel and start the Add/Remove Programs. When I did that, I noticed a rather strange thing in the list of software that I have installed on my laptop. None of the software in the list has the usual Change/Remove button available, except for the very last one. All the buttons went missing. At first I thought it was just that particular program which I intended to remove. But as I checked the other software in the whole list, they were all missing the button.

My first response wold be to Google for an answer. Apparently this isn't an uncommon problem. I found a forum which has a number of people experiencing the same problem. Although I did not find the reason for the problem, I did find some hints as where to look further. I checked the Windows registry using the regedit command using the MSDOS command prompt. (Warning: unless you know what you are doing, I suggest that you do not try to make changes to the registry. Making the wrong changes can cause you more problem and headaches. Notice that this article is tagged as Advanced?). The uninstall information could be found in the registry entry: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall. You should be able to see a list of programs that are currently installed on your computer. These are the settings for uninstalling each one of those Programs. In my case, there was only one program listed there. The first thought that came to my mind was "Oh no. Does that mean I have to re-install all the software again, just to get those uninstall information?". I refused to accept that seemingly doomed option and began to think of how I could restore the registry, if I could.

The first option I would pursue would be to do a System Restore back to a previous system settings. This can be accomplished in the program called System Restore which is found under All Programs/Accessories/System Tools. To my initial joy, there was a copy made just a couple of days ago, which I suspected to be the day when the whole problem began. And I proceeded with the System Restore, even though it would mean losing a couple of changes I have made in the last 2 days (I have previously installed 2 new software). Having done that and a system reboot, I got the message that the System Restore was unsuccessful, for whatever unknown reason. So I tried the next earlier copy which was a week old, hoping that this one should do it. Again the restore was unsuccessful. I did not want to go too far back because I do not know what changes I have done that would be lost in the restore process. Time to come up with another option..

By a stroke of luck, as I have mentioned earlier that I had a Trojan problem on my desktop. And I also ran a Spybot check on my laptop. As part of the process, I have backed up the Windows registry and hence have the backup file somewhere. Again with Google I was able to find out where this backup file is. And thankfully those missing registry entries were backed up in this file. And I did the followings:

1. Export the current registry entry for HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall. to a file. This only contain one program entry, the last one.
2. Extract the rest of the entries from the backup registry file made by Spybot.
3. Combine it with the one I just exported in step 1. Since these are plain text files, it is a simple process of cut and paste.
4. import all the entries from this file back to the Windows registry.

Thankfully it worked. Like I said I was lucky to have a recently backup copy of the registry. Otherwise it may be more challenging to restore.

I can't just let this go without trying to figure out what caused these registry entries to go missing in the first place. I'll probably never know for sure but I suspect that it has something to do with the re-installation of the Zonealarm software on my laptop. Why this happen, I don't know. Since this was the only program entry in the Add/Remove software list, I suspect that it is the culprit. And because alphabetically it was the last entry, and every entry before it, was deleted somehow. Anyhow I am quited pleased that the whole process wasn't more complicated and that I did not need to go through the process of re-installing all the programs (I have quite a number of them). That would have taken me many more hours.