Windows 98 only boots to Ms-dos

I?m working on a computer that does not boot into Windows (98). It boots into Safe Mode but not Normal mode. Normal mode gives no error only a command prompt. I have tried checking MSDOS.SYS, AUTOEXEC.BAT, and CONFIG.SYS. In MSDOS.SYS, the GUI is on. Remarking lines in AUTOEXEC.BAT and CONFIG.SYS did not help. Extracting HIMEM.SYS off the cd-rom also did not help. Step-by-step gets to command.com and that?s it. I get to the command prompt. If I type in Win at the command prompt, it will say that you are in ms-dos mode and to restart in windows type y. It takes me back to the command prompt. The customer claims that nothing was added or removed from the computer. He says it just started happening. Thanks in advance.