MSDOS.SYS is a hidden/protect file - chaning the option to display hidden files in the folder options has no impact on the protected files they will still remain hidden. To display all the files in a my computer window, click Tools/Folder Options/View and uncheck 'hide protected operating system files'.
Then right click on MSDOS.SYS. Select 'properties,' then uncheck 'read-only' and 'hidden.'
Edit MSDOS.SYS using notepad. Add these under the [Options] section:
Dblspace=0 This will tell the OS not to load the DoubleSpace compression program during boot up, thereby freeing up memory and reducing an unnecessary program from running. Do not use this if you are using have a compressed hard drive!
Drvspace=0 This setting tells the OS not to load the DriveSpace compression program during boot up, thereby freeing up memory and reducing an unnecessary program from running. Do not use this if you are using have a compressed hard drive!
Logo=0 This setting will disable the Windows start-up logo during boot, thereby reducing time to load. If you like the Windows logo, don't use this setting.
Bootdelay=0 This setting tells the OS not to delay when switching from your BIOS POST to the OS boot up. Although most users already do not experience a delay, this guarantees that you have a zero delay.
Disablelog=1 This setting will disable all event logging that occurs during boot up, thereby reducing the amount of time wasted to perform this task. If you wish to have your boot up logged, usually in order to find errors, do not use this setting.
Doublebuffer=X This setting tells the computer whether or not to use double-buffering for your hard drive. If you have a large FAT32 partition or you use SCSI, I recommend that you enable this by inserting a 1 for the X. If you have a smaller FAT32 partition (under 10 GB per partition is a good rule) or you still use FAT16, I recommend that you disable this by inserting a 0 for the X.
Be sure to save MSDOS.SYS as a text (ascii) file.