windows wouldn't start after back

I had a backup file (disk, partitions, mbr) on my internal back up drive. I had some problems so i decided to do a restore. It ran the restoration before boot and completed 100%, upon restarting it said it was missing some boot files. I managed to repair it with my Windows CD, but was wondering why this may happen. Does it have anything to do with my backups being compressed?? Im no comfortable with this as next time i may not be so lucky.

Hi

It doesn’t have anything to do with backups being compressed.

What Windows do you have?
Did the restore process reported any errors?

Thanks