failing attr : 05

Can somone help me i am tryin to fix my laptop every time i turn it on it comes up with the message 1720-SMART Hard Drive detects imminent failure (failing attr : 05).
now i googled it and people say you have to replace your hard drive now i want to save everythin on the hard drive but every time i press f1 to ignore it comes up a message sayin

(windows could not start because the following file is missing or corrupt:
\windows\system32\config\system
you can attempt to repair this file by starting windows setup
using the original setup cd rom.
select r at the first screen to repair.)

Now i dont have the cd rom and i dont no if it will make a diffrence can someone help me here please.

 

its a compaq evo n800v

 

thanks very much