At first, please check whether your original files are not merely hidden by the infection. More information on how to display hidden files can be found here.
If you find your files, simply remove all the detected Trojan horse files and remove the "hidden" attribute from your files. That could be done as follows:
1. Select all the files you want to remove the "hidden" attribute from.
2. Right click one of the files (while the files are still selected).
3. Select Properties.
4. Under Attributes, untick the Hidden item and click OK.
To make sure the infection is completely removed, we strongly recommend running thorough AVG full computer scan as described here.
If it is not possible to find your original files, it is likely we can't recover them. However, I can't tell for sure; to be able to analyze the issue in details, we need diagnostic data from your computer. Please either contact AVG customer care experts or describe the issue in AVG Forums.
I really need your help. I'm desperate, I cannot access my very important files saved in folders stored in external hard drive because these are infected with Trojan horse Agent3.MCF.dropper, and my AVG antivirus (free download) cannot heal them. All folders into which the files are stored are changed to "application" type of files (88 KB). I also find it strange AVG ThreatLabs cannot recognize this specific virus. I even tried AVAST free antivirus, but to no avail. I searched the web for online solutions but I cannot figure out which one to follow. There were many suggestions and "how-to's" but I find them very hard to follow considering the very lengthy instructions. I'm sorry for myself I'm not really a hi-tech guy. Hopefully somebody can help me. I need my file back. To you who can help me, thank you very much in advance.