Hi

I'm very new to this game and still having difficulty understanding when cards can be trashed.

My main question is, does a card have to be unrezzed in order for the runner to trash a corps card or is he able to trash an asset or upgrade which is rezzed?

Any help gratefully accepted.

The runner may trash a card with a trash icon, regardless of whether it's rezzed, when the Runner accesses that card.

Just to be clear:

When you run a remote server succesfully then you access all the upgrades/assets/agendas in that server.

When you run HQ the random card you look at is "accessed" so you can trash that if it has a trash cost. (and you access the upgrades on HQ root of course)

When you run R&D the card you look at is being accessed as well. (and upgrades on the root)