Programs freezing up

Just recently I've started having problems with programs freezing up. It seems that everything else is fine until I start to do things; such as simply clicking on the start button for example. The menu pops up, but it sticks and that freezes, too. I can open windows such as 'my computer', but nothing happens when I try to go from there.
Also, a few moments after windows starts up and gets going, an error message comes up "an error occured in 0x###### in memory 0x0000000.

Does this all mean that I have a bad stick of RAM?