If all the Restore Points are corrupted, they're useless and may as well be thrown out by turning System restore off. Post some details of the problem you're trying to sort out and someone will have an answer - just make sure you turn SR back and create a new Restore Point when you've finished dealing with the problem. When I turn it back on, I always reduce the hard disk space to 5% because I believe you get fewer but better quality points that way. Opinions on that will vary but it works for me a my customers.