ok, here's what i did and it worked fine.
first, download a copy of iertutil.dll off the internet
Second, put that file on a usb (it's easier if that's the only file on the usb)
Third, restart your computer in safe-mode with command prompt
Fourth, put usb in computer and enter the following into the command prompt
"copy *:\iertutil.dll c:\WINDOWS\system" -minus quotation marks, and * is the drive letter of your usb eg mine was 'G' so
g:\iertutil.dll c:\WINDOWS\system
that, as you might have guessed copied the iertutil.dll file from your usb to your WINDOWS\system directory
once that's all done restart your computer and it should be fine
note: if additional error messages like the first one come up, saying that a file is missing, just repeat this process with the different file and appropriate directories
Hope this helps