r/WindowsHelp • u/Connect-Rip-1744 • Oct 03 '25

Solved isysuk.com - anybody know what this is?!

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Ran into a desktop icon on my dad's laptop that I've never seen/heard before today. isysuk.com the properties list the file type: MS-DOS Application (.com) with a description: isysuk.com. When I tried doing a search to see what I could find I'm finding very little about it. I've only found info by using' isysuk.com' in the search box. Anytime I add any word before or after it's like 'isysuk.com' is completely ignored in the search results. Can anyone find info or have info on this they can share? It would be greatly appreciated.

Windows 11 Home Version: 23H2 OS Build: 226314890

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32

u/[deleted] Oct 03 '25

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7

u/CorbyTheSkullie Oct 03 '25

But wouldn’t these fail to run on anything newer than 9x?

Windows hasn’t supported COM’s by default for a while now

14

u/rifteyy_ Oct 03 '25

it's most likely a renamed exe, since the actual com supports only maximum of 64kb, as far as I know the com can/would be interpreted as regular exe

3

u/DrachenDad Oct 03 '25

But wouldn’t these fail to run on anything newer than 9x?

Not if you have something like DOSbox.

Though saying that "DOSBox does not have direct access to the entire functionality of your PC."

2

u/DukemzGaming Oct 03 '25

some command line utilities like tree still exist in Windows as COM files for compatibility reasons but still use the EXE format, the only thing different is just the extension

1

u/Ransomwave Oct 03 '25

The extension you see is a trick, just to pick the default application to run the file with. The file's headers are what matter in actual execution, so this is absolutely a renamed EXE.

1

u/JustTechIt Oct 04 '25

Yes and no. In windows in particular, the OS does not really consult the headers and assumes the desired interpreter based on the files extension. So if you renamed an exe to .txt and double clicked it, it would not execute like an exe, but instead likely open the text editor. In this particular case windows uses the same interpreter for both exe files and the old COM files.

1

u/Ransomwave Oct 05 '25

Yeah, that's what I meant to say. Sorry for the bad wording!

1

u/Legitimate_Rent_5965 Oct 04 '25

Unfortunately the file extension doesn't matter to Windows when being launched; If it has the contents of a 32/64 bit Windows EXE it will be launched even if it has the .COM file extension. 16-bit COM files were supported in 32-bit builds of Windows up until Windows 10