Beginner Help

Q1--yes you can...or you can just take the AdSense ads off that particular website.

Q2--No. Publishers are not permitted to maintain multiple AdSense accounts under the same payee name. However, you may add other websites to your existing AdSense account.

Q3--Here's what AdSense says--"We'd like to remind you that once you've been approved for AdSense, you can place the code from your account on any page that complies with our program policies. Simply generate new code and paste it onto your site -- we don't need to update your account, so there's no need to contact us about your new site (although we appreciate the thought!). Even if your sites relate to completely different topics, our system will display appropriate ads for each site. This is because your ad targeting is based on the content of your pages, rather than set within your account. In addition, please keep in mind that publishers may only maintain one account per payee name, so there's no need for you to submit a new application."

Q4--check this webpage out for the answer--http://www.nerdgrind.com/tracking-multiple-domains-with-google-adsense-analytics-code/

I hope this helps!