Some more WM Newbie Questions

[rfox]

Please excuse my very newbie questions, but I don't have a WM device yet to test these functions out. Finding out as much about WM will help me when I do get one.

I've been seeing a lot of posts (here and elsewhere) about changing ROMs, flashing ROMs and being weary to not turn your device into a "brick".
If I'm understanding this, I don't think I would ever need to do anything to the ROM if I just want to add apps and files.
1) But would just doing, that is the applications themselves, alter the ROM to where it gets corrupted and need to be reset?
2) If the ROM does get corrupted (turned into a brick), can't you just do a hard reset to restore it to factory condition? Or would that be device specific?

Do you have to get applications that are built for your device resolution?
Obviously, a larger resolution app won't work on a smaller resolution display, but can you run smaller resolution apps on larger resolution screens? Does the apps just rescale to fill up the entire display or does it put the app in a window?

Is there any kind of command or terminal window function that you can enter commands directly?

I've tried to find info on setting up a VPN connection, and apparently ther's a built-in VPN client feature in windows mobile? How does it work, or is it better to get a 3rd party VPN client instead?

Thanks for all your input.