Rescatux is a good balance between powerful features and relative ease of use. Ultimate Boot CD (UBCD – http://www.ultimatebootcd.com/) has more tools but is a bit less user friendly.
More info on Rescatux at https://www.howtoforge.com/tutorial/how-to-rescue-your-system-with-rescatux/ 
How to Rescue your Windows or Linux System with Rescatux
How to Rescue your Windows or Linux System with Rescatux