Website has malicious software and stops AdWords.

If you have a lot of website traffic and are having your website hosted with a third party with low level security on the servers you may encounter someone with a little more time on their hands than you and decide to hack the server.
Now when you go to your home page it says the site may contain malicious software and you have an option to continue to the site at your own risk.

1. Step one is contact your hosting provider and have them clean up the server so that you may be reconsidered for your listing.
2. After you are cleared you need to use your webmaster tools to request a reconsideration for your adwords account and your listing with Google search engine.
3. Wait about 24 hours and if the malicious software was cleared you should be good to go.

Don't blame the hosting company in this instance, there are just people that are "malicious" and wanted to have fun at your expense.