Back up failed---how to fix

I am running Win 8 and Norton 360 and multiple times I have had it come w/back up failed.  Eventually it does back up.  I have another back up program so I'm not too worried. But I paid for 360 to do what it is supposed to do.  How do I fix this.  And please don't tell me it's because of the other program.  They've been running together ever since I've had 360. Likewise I run other anti-mal/spy/adware i was having problems w/the back=upprograms.  I did that because of continuos infections.  The first time I ran SpyBot, it detected all of those I had been battling for weeks.  And it isn't them.  I was having the back up problems before that.