Stuck in a software time warp...

I'm so outdated. In my graphics classes we've been using some software that I'd never had the opportunity to use before (QuarkXpress, InDesign, etc) which has been a memory confugulation trying to remember where on the menus things are at for like 4 different programs. But finally on a project we started this week I was able to use Photoshop which I've been using for, oh, about 9 years now... and I'm thinking I know this program. Welllllll, unfortunately my Photoshop at home is just a leetle bit outdated. Without all the upgrades I didn't keep up, so the latest version is practically like learning another new software program. Just a simple function was giving me fits... with my OLD program I simply draw a selection square around something, hit the delete key, and *poof* it's gone. I cannot seem to do this with the new one. I don't know why... it wasn't a wrong layer or anything easy like that. I know there's a way to do it, but I have to go in circles for 15 minutes first. Why didn't they just add new features to the updates, rather than change the standard functions? Grrr...