Automatically back up files to external HD's

Hi all,

I suppose this may have been asked before but not sure where to start.

I had a near loss of files the other day when my PC appeared to stop working....thankfully now ok again.

However, despite the fact that I have 2 X 500 hd external drives and 1 TB external HD (all western digital) I simply failed to back up files regularly...

Is there a SIMPLE program which allows me to,

back up all files to external drives,
automatically overwrite exisiting old files etc
do so at a set time every night...
Perhaps back up between drives once copied to one etc

Any help would be much appreciated.......lesson learnt!

Best wishes

Ray