When I start up my computer, I get a line that says something like, 'unable to find ms dos files, ms dos startup failed'. Everything else works fine though and I can use dos through windows. I also don't have a C:/Dos folder. Any suggestions?

OK what version of DOS are you useing?

I think version 7. The run-of-the-mill one that comes with win98.

Hello,
Win '98 is called DOS 7.1 internally so in fact Microshidt admits with this item that Win is in fact STILL that old fashion DOS-SHELL as it started as.
Win '98 uses X:\windows\command for the dos parts, there you'll find EDIT, FORMAT and most of the other DOS programs.
win98 does not need normal CONFIG and AUTOEXEC but if some is filled-in in these it will execute as normal (is DOS) start-up,
so if you gave directions for DOS in a normal way it will not find it.
You can "empty" your system files by just renaming them in an bit different name like *.bot or *.sis BUT FIRST MAKE A START FLOPPY!!!(boot flop)
do this with a empty(new) flop and type
SYS a:
this will make a basic flop with COPY's of
IO.sys (hidden)
MSDOS.sys (hidden)
Command.com
autoexec.bat
config.sys

I hope this helps you.
The error might be a wrong re-direction.
Succes Chris