Wont boot...cant find file msvcrt.dll

Try to help a kid that "just deleted a few files" to try
and free-up some disk space. The computer continued to
work after the delete actions, but when she rebooted,
during Win98 start-up the following error came up:
"Can't start explorer, file c:\windows\system\msvcrt.dll
is missing'. I also can't boot-up in safe. I did boot-up
to a dos prompt and went into the 'recycle' folder and
attempted to move some D??.EXE files that were listed back
into c:\windows\system and then renamed them one at a
time, but this did not work. Any ideas anyone?