A registry defragmentor program caused my sysem to not be able to boot. The system could not repair itself either. I also tried last known good configuration without results. I tried to do a system restore and had a number of restore points to choose from, but every one I chose gave me an exclamation mark and I could not put a check mark in the C Windows box. I was able to get my system back using another backup routine (image) I was using, but this backup was 3.5 weeks old and I had 3 restore points for 3 days ago. So what might I do to get this working in case a similar event happens and my system is unrepairable via the repair tool presented. Windows 7 home premium 64 bit.