Installation error

[Guest]

When I try to install some programs, I get the following error:
16 bit Windows Subsystem

C:\WINDOWS\SYSTEM32\AUTOEXEC.NT. The system file is not suitable for running
MS-DOS and Microsoft Windows applications. Choose “Close†to terminate the
application.

Can you help me? Any help will be greatly appreciate it.
Thx.

 

[Bob I]

Likely cased by a malware infection

Error message when you install or start an MS-DOS or 16-bit
Windows-based program
http://support.microsoft.com/kb/324767/en-us