I had a Trojan on my Dell 8400 that Zone Alarm Malwarebytes and Combofix all missed. I found it by accident and removed it manually following the instructions I found on a website. Unfortunately, I then got a Windows message that said some of my Windows files had been altered (presumably by the Trojan). Windows asked me to insert an SP3 Pack DVD in order to fix the problem it had found.
Since I didn't have this DVD I decided to reinstall Windows XP Professional. The reinstall went find, but when I checked my PC I found that Windows was no longer recognizing all the software I had previously loaded, nor the icons I had placed on the Desktop.
I placed all my old shortcuts back on the desktop and reconfigured the desktop using the Display option in Control Panel as the first step in rebuilding my system. However, when I rebooted my system the next day, I found all these icons had disappeared and my reconfiguration of the Desktop was gone.
While all my previously loaded programs were in the programs folder, none of them were in the Start Menu 'All programs' folder.
Also a lot of my programs either no longer or run or load as trial versions. From this I assume the Windows reinstall replaced the old registry with a completely new one and I've lost all my licenses and such.
I made two copies of my old registry just before I reinstalled Windows (one with Combofix and one with Advanced System Care. My question is: will I create any problems if I restore my old registry? Also: do I need to use Combofix to restore the copy of the registry that it made and Advanced System Care to restore the copy of the registry that it made? Or do all software utilities backup the registry using the same format?
Finally, what the drivers my old programs used. Does Windows have a drivers folder? Will I need to reinstall all my old drivers to have my programs run as they once did?
I would very much appreciate any help that anyone can give me. I don't want to have to reinstall all the software that I've painstakingly put on my system over the last few months. Some of it I probably can't reinstall as I downloaded it from GiveAwayOfTheDay (you can only install their free giveaways on the day of the giveaway).
...AND, install all drivers, starting with the Chipset driver, then video*, Sound, SMBus, Microsoft UAA Bus Driver for High Definition Audio (if you have HD sound card), Windows Installer 3 or higher, .NET Framework: 2, 3, 4, Direct-X 9c (latest), Networking, , everything... until there are no more yellow exclamation marks in front of devices in Device manager. Then you can start re-installing programs you like.
*Video driver may require .NET Framework 2.0 or higher to be already installed if an application is supplied with the video card.
Thanks for the advice, but I've already downloaded the Dell drivers on another PC and installed them on the previously infected PC.
Since posting my problem, I've discovered that my old Windows XP Professional is still on my machine. I'm trying to deal with my problem by running SFC /scan now and reinstalling Service Pack 3. So far so good.