My Windows 95 Laptop Will Not Boot, What Should I Do?

I can not get my Zeos Meridian laptop to boot it's operating system - Windows 95. It once booted, but now it says "Starting Windows 95..." like usual, but it goes to a DOS prompt. I type "CD WINDOWS", then "WIN" at the "C\WINDOWS:" prompt. It says check your windows directory, HIMEM.SYS is missing. I checked, and it was clearly under the Windows folder (Directory). Please help!