Hey ppl, I'm using WinXP , just today the system is refusing to start any MS-DOS applications. It just gives a error in a message window with the title as ' 16 bit windows subsystem ' and the exact error message within the window is as follows ' 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 ' The choices it gives are close or ignore , both of which when selected just return back to the system. Everything else works fine, ie all the windows applications work fine , but none of the applications which run on MS-DOS like TALLY 5.4 etc... work and give this same error message . Hope u guys can help !! My e-mail address is firstname.lastname@example.org Thanks Huzefa.