It appears that your himem.sys file is corrupted or missing.

config.sys line 2 error is probably calling for this file.
Open the file with notepad.exe and see.
(or boot up w DOS floppy. type: Edit config.sys or open config.sys)


if so, simply copying the himem.sys from your DOS disk could fix the problem.

****
himem accesses the "extended" RAM memory and loads DOS there. without it, DOS is loaded into the Base memory.
(the original 640K of RAM. and the only true "Working section of RAM".)

legacy of the "Original Sin": in the days of the original PC (XT) 8080 intel
that 640K was an "almost infinite" size of RAM
since most programs in DOS were 1k 3k 5k etc.

(There are actually 3 sections of RAM (stupid microsoft) patches, patches.
BASE RAM
extended RAM
expanded RAM


*****OR----*****
simply copy himem.sys from DOS floppy to HD dir called for, if it works; then you know what it was. no need to verify by opening files, etc.
but at least you know what is taking place. in the OS

Al Castañeda