browser ui

i have a friend i been trying to help for 4 hrs
right
her pc is not loading up explorer
it comes up as could not find
browserui.dll
thus no start tab no desktop icons
i tried going through task manager to restore pc but the restore window was
blank
there is no reboot disk how can i reboot its operating system from factory
settings?
i coulnt even try it in safemode
like a virus wiped the file or something
thx in advance
john