Dear T291,
Yes your system files are corrupted so you are getting this message. If you have same installation media through which you installed your existing corrupted windows, use that CD
Boot your System from CD ROM using Windows Installation media
Select Repaire option by pressing R key
After Command prompt coming type your administrator password (If you have)
Select 1:Windows (If you have one Operating System in ur system, if not select your operating System No i.e. 1 or 2 or 3)
now you will be redirected to command prompt in C:\
Now type chkdsk /r
Wait for mew minutes (It may take upto 1 hour, depending on your system configure)
After completing the same you will back again in command prompt
Now restart your system
All of your data will stay in save mode, nothing will be erased if you used this repaire option. If you format, you cant get any data, otherwise you have to recover all data using another Data recovery application