I was checking out the high res texture pack, and I accidentally clicked for it to install but I don't want it to.

Now it says that Skyrim is updating and will not let me launch it until the update is complete. The update is 3Gb apparently and I have slow DSL so I don't want to wait for it and I don't even want the texture pack at all.

Can anyone tell me how to stop this?

You'll have to contact Steam support and have the pack removed from your account.

Until then you could try and play offline.

Thanks, I put in a ticket. I have no experience with Steam Support because I am new to PC gaming.

So do you have any idea how long it usually takes to get a response?

For a straightforward request it shouldn't take too long.

Will depend on staffing levels over the holiday, though.