Ms-Dos Based Program

Hi, I have a computer running win98 I install a msdos game program and it works fine the only thing is that after i reboot the comp i can't boot to windows the game would start after restarting.. Then i quit the game the comp goes to the c: prompt and then i type exit or win and i get a message "You are currently running in MS-Dos Mode. Do you want to return to normal mode, to run win applications again? I put Yes and again the same message appear.. I delete the lines of the prog on the autoexec.bat and config.sys and i still can't boot to win
i will appreciate any help,

thanks

Ismael