Yes, you can have more than one Facebook account from a computer. However, you can only have one Facebook account per email address.
No
You are only allowed one account, as per Facebook rules. If Facebook suspect that two accounts from the same IP's are the same person, they will disable both accounts.
Yes it can.
You can install one dropbox client in one computer. If you want use two Dropbox accounts then sync 1st account and after that log-in to other dropbox account.
as long as you a different email address and password for each of the accounts it will allow you to create as many accounts as you want, just sign out of one, and at the log in screen, select create account
Yes it is possible but it cannot be under the same email address you would have top make a new email account in order to do this
you can't
you can't
yes
You'll have to pay twice, but you can save two usernames on one computer. Switch when you open the launcher.
According to Facebook: Maintaining multiple accounts, regardless of the purpose, is a violation of Facebook's Terms of Use. If you already have a personal account, then we cannot allow you to create business accounts for any reason. You can manage all the Pages and Socials Ads that you create on your personal account. You can read their full terms of service at the related link below.
You can't share a game between two accounts on steam, you'd have to buy the game again on the other account.