Helping people with computers... one answer at a time.
There are a couple things to check when a 16 bit MS DOS Subsystem error pops up on your machine.
I get this msg when i start up my computer.
16 bit MS DOS Subsystem
The system is not suitable for running MS-DOS and Microsoft Windows applications. Choose 'Close' to terminate the application. I did not have this before. Please advise me how to fix this problem.
While there are a couple of clues in that error message, the results are inconclusive.
The 16 bit subsystem is what allows some older MS-DOS software to run in today's Windows NT and XP. It sets up a simulated MS-DOS environment, and many old applications can run fairly well. (This not to be confused with the Command Shell, which is a true 32 bit Windows application.)
But in this case it looks like some old 16 bit MS-DOS application is attempting to start when you log in. In fact, it's possible that the 16 bit debugging program debug.exe is being started.
If you had just installed some new software, I might suspect that as the cause. Especially if it was a new install of some old software package. However my assumption is that this isn't the case.
So I would do three things:
I actually suspect spyware, but I've not seen one that starts a 16bit program before. In any case, since it's trying to start when you start up Windows, the last approach should allow you to disable it if the spyware and virus scan don't stop it.