When I start my Acer

Question

When I start my Acer Aspire3650 it says "Windows could not start because the following file is missing or corrupt: \WINDOWS\SYSTEM32\CONFIG\SYSTEM You can attempt to repair this by starting Windows Setup using the original Setup CD-ROM. Select 'r' at the first screen to start repair."I haven't got a CD-ROM, I was never given one. What do I do?