It shows everything that starts at PC startup. (When I install a new PC for a user, I even run this). Things like Adobe has things running at startup to speed up their product (but if you rarely use their product, no point having it run in the background - just take the extra 2 seconds later when you do actually start the program).
Anyway, this program allows you to right click, and "disable" something from starting - Of course I guess I should also warn if you don't know what something is - it either means it might be very important where you don't want to touch it - or some kind of spyware messing things up. So be carefull when using it.
Oh, and more memory will always help. 512MB is not much anymore - if you can upgrade it at all - even to 1 GB, you will find it helping a lot.