16 bit MS-DOS Subsystem = Error in Windows, what should I do?

Question

16 bit MS-DOS Subsystem = Error in Windows, what should I do? C:\win1.pif Invalid program file name,please check yout pif file. Choose 'Close' to terminate the application. Whenever I start window XP, above mention error comes & whenever i open a new window this error comes again & this error continues to come from C:\win1.pif to C:\win20.pif with the same message that it is "Invalid program file name,please check yout pif file. Choose 'Close' to terminate the application. " I just have to click ok, the window on which it comes dont really terminate after clicking ok. what should i do to get rid of this error? I SIMPLY CAN'T RE-INSTALL WINDOWS XP, so plz suggest any other option. Thank u in advance