Volkswagen Repair: 2000 VW Jetta 1.8T - starting problems, jetta 1, vw jetta

Question
I have a 2000 VW Jetta 1.8T.  About a week ago, after driving about 20 minutes to work and working for 8 hours, I got in my car and it didn't start.  It didn't even turn over - - but the radio came on.  No clicking even.  I waved my friend down who was leaving and was getting ready to ask for her help, when I turned the key and it started.  I thought maybe I was just tired and didn't turn the key completely or something.  

Then today, about a week from the first incident, I again drove for 20 minutes to work and worked for 8 hours.  When I got in my car and attempted to start it, the same thing occurred as the first incident - - it didn't turn over - - didn't even click, but the radio came on.  I turned the radio off and tried to start it again.  Nothing.  I tried a few more times with no results.  I popped open the hood and looked at the battery cables.  One of the connections has a lot of white build up on it.  I just felt the connections a little to see if they were secure, which they seemed to be and then tried to scrape a little of the white build up off and tried to start the car again.  Nothing. I tried again and it started.  

Can you tell me the possible problems could be based on my experiences?  Could the white build up cause my car to fail to start abruptly like this?
I appreciate your help.

Answer
Cecilia,
 The white build up is corrosion, this is not unusual but not good.  The short answer is yes, this could cause the problem, but there are other possibilities.   However I would start by cleaning the battery terminals.  They should be disconnected to be cleaned effectively, however you should use a "memory saver" so the ECU and other electronics do not get reset, which could cause other problems.

Rick