IFSHELP.SYS and VMM32.VXD

I have windows ME on my computer, now when I start my computer I get these messages on DOS.
the follwing file is missing or corrupted
C:\windows\IFSHELP.SYS
the following file is missing or corrupted
C:\windows\system\VMM32.VXD
C>

Then I can not do anything
I want to reinstall Windows if this will solve the problem.
What should I do
Thanks
Sohail Rizki
713-350-2832
713-350-2001 fax