the first time you run any internet enabled application the windows firewall (in windows 7 and im assuming 8 ) asks you if you want to allow that application to talk to the internet.
if you say yes then those ports are opened up automatically, if you say no then the app is dead in the water and windows wont ask you again next time you run it.
if you run a new version of the client from a different folder windows will ask you again if you want to allow the app to talk to the internet..
also you don't need RPC port and Daemon = 1 and Server=1 for running the client as a wallet only.
they are used when the client app is running as a daemon so you can do funky things like run mining pools and web services against and tell it to do things remotely etc.
all of the RPC settings should be kept TIGHTLY under lock and key (ie dont tell anyone) because if someone has those settings and your IP address they can tell your client to do things like send money remotely (if your wallet is unencrypted, which it is by default for every new wallet)....
if those are your RPC username and password then I suggest you change them since you just told everyone..
normally yes. but it doesnt right away. if you install a wallet and the wallet has the port at 10000. firewall will block it with out a prompt. if you re-start your comp and then run the wallet you will get the prompt
by introducing a new configuere file and set the port to more firewall friendly ports between 8800-9999 then you can synch up with out having to create firewalls prompts
only the rpcpassword is dangerous to share. (of course i didnt show my pass nor the port i am using ) But the level of you getting hack its not that great. those port are port that windows firewall and antivirus monitor hevely. especially port lower , like pools use. I am not worried.
but since these users just recently installed the wallet. they must have not restarted their comps yet. or windows firewall does not give the promt to unblock. it just blocks it for them automatically. I am confident that if they put the addnodes i suggested and use a port number between 8000-9999 they will synch right way.
also by setting up the configure file i also solve any future question if they want to solomine : )