Software Update?

Hi, I did a software update on my black macbook of 2007 last night March 6th. This was the software update icon at the bottom jumping up and down. I close the programs im working on and click install now, typed in my password and let it restart. Well, apparrently it didnt tell me what was the update. I don't use the mac as my primary computer. I've only used iTunes, 3 websites (I know, I'm strict with what I go to). I looked at the installed updates and doesn't show anything from March 5th. The last update was Jan 9th.So I don't think there is a trojan or virus being downloaded but i just want to be safe, what do you think?