I think i could help you craig but first i need to know what hardware came with your protools (mbox, digi002, comando).
answers:
1. digidesighn created protools to only work with their hardware so you will not be allowed to configure the program to recognize your already existing soundcard. you could do what i did and take the outs from whatever hardware came with your protools "in my case the mbox", and rout them to the inputs on your sound card. then you will get sounds coming from protool to go through your existing sound card.
2. "this answer is for question 2 and 4" whatever hardware came with your protools should have mic inputs, so plug your mic to one of the inputs and remember the mic input number. make sure if your mic requires phantom power that the phantom power switch is on on the protoos hardware. go into protools and to create an audio track, you do this by going to the file menu on the top left side of your screen and selecting new track. now you get the option to select how many tracks, mono or stereo, and whay type of track midi, autio ect... you should select mono, and audio track then click on the create button. once your audio track comes up then click on the mic/line tab for that audio track. if you dont see the mic/line tab for the track then you need to bring it up, you do this by clicking on this icon on the left side of your screen near the top in side the black bar that goes accross the protools woking surfice. the icon dosent have a name is just the first on from the left. when you click on that icon then you select the I/O view and the mic/line tab along along with other options will appear. click on the mic/line tab and go to the interface option and select the mic line number that you have your mic hooked up to. now you set that track to record ready and you should be able to hear sounds coming from your mic. to record vocal you set the track to record ready and click the record buton on the transport panel. to select a diferent track to record on just select the track and click on the R to set the track to record ready.
3. to undo a mistake go to the edit menu right next to the file menu and there you will have your undo and redo options.
if you got more question just hit me up
oh! if you got the free version of protools then you need to check with the protools websight digidesign to see what os are compatile and also what soundcards are compatible with protools free.