Exe files are executable files used to run programs in Windows. These files have the .exe extension. Svchost.exe, Iexplore.exe, and outlook.exe are a few frequently run exe files in the Windows system.

Common EXE Errors
If you are unable to run a program or application on your system and are encountered with frequent exe errors, then the presence of a malicious software might be the reason. Viruses such as W32/Swen.A@MM (Swen), SirCam, and Pretty Park can modify the Windows registry to change file associations of exe files and stop them from executing. When this problem occurs, you cannot open any program or application, such as Internet Explorer and Microsoft Word on your system.

These errors might also generate logon problems and prevent you from gaining access to your system. Svchost.exe file that is located in the system32 folder of your system is used to check the registry for services that must load at startup. Many important Windows services pertaining to the logon, spooler, and network processes are loaded using the svchost.exe file. Therefore, if the exe files fail to run on your system, many important services may also fail to start. 

How to fix
The best way to fix virus infection-related problems is to update the antivirus software on your system and run a virus scan. Most of the antivirus software available today continually update their virus database and ensure that your system is free from any type of virus infection.

Many antivirus websites also enable you to download virus-specific tools. These tools scan through the registry and system files to remove any modifications done to the system by the virus. You can search for these tools by entering the error you are receiving in a search engine.

These websites also provide methods to manually remove virus-specific entries from the registry. To edit the registry, you need to open the Registry Editor Window by running the regedit.exe file. On an infected computer, where you are not allowed to open any exe file, you will first need to make a copy of regedit.exe with the name regedit.com. For this, open command prompt, type 'CD C:\Windows' and press Enter. Next, type 'copy regedit.exe regedit.com' and press Enter. Exit command prompt and run Regedit.com to open the Registry Editor. Now, refer the virus-specific removal information from the antivirus software web site and amend your system's registry accordingly.

You must be very careful when making any manual changes to the registry.

Unless you really know what you are doing, it is never advisable for anyone to start playing around with the Registry of
their PC. 

Simply put, if you mess up the Registry and the operating system of your computer, then the whole Windows shooting match can just simply cease to function - entirely.

The best answer when making any kind of repairs to any part of the Registry and the Windows operating system of your PC is to use a proper professional Registry cleaning software program, something like the award winning Registry Winner.

Firstly, you can use the program to run a complete deep system scan of your PC entirely free, in order to locate and isolate all of the problems that you have within the Registry files and folders of the Windows operating system.

This would include any and all damaged or corrupted .exe applications, as well as any .dll files that might be associated with those .exe folders.

Them you can simply use Registry Winner to fix all of the .exe errors that it has already highlighted in less than five minutes, in a safe and stable manner.

Basically, it is nothing more than using the correct tools for the job.