Nothing prevents you from managing as many adsense accounts as you want from the same ip, same computer.. Just not for the same person. There is nothing against it in adsense's tos. Now if one account is banned for invalid click activity, then the others will be at risk to be banned too for being related to the fraudulent one. But if you manage them correctly, what's the problem? If you have been doing shady things, then of course you have things to fear, just a question of time.. but if not, don't worry about anything!
Sorry, its not possible to operate two ad sense account on same PC and IP. Do you currently do this or have you tried opening another ad sense account with any success? I don't think so. You will be bold inform that an ad sense account is associated to your account or something similar. The big G made it clear that one ad sense account to one person, they use their bot to keep users glue to one PC/IP and the bot does not recognize human finger print/face just the PC/IP.
I'm managing five different adsense accounts from my computer, the worst been happened is when some sites are disabled ads on some accounts, but the accounts are okay. Google knows that IP address is scarce and I don't think they prohibit some persons in one household (which most of time means one IP or even one computer) to have different adsense accs, what's wrong with that? What is wrong is when we do invalid clicks. Indeed, there's a greater risk when one acc got banned, the others will be in danger. But I'm willing to take the risk rather than to put them all in one basket/acc.
I live in a household of 5 and 3 of them are also webmasters. All 3 have signed up for google adsense and applied to their own website, we have had no problems for 3 years. And we all registered under the same ip address.
I think it is a combination of PC no, IP and address that counts when it comes to being banned by Google AdSense
You should not use two adsense from one ip because if google will observe it then you might get banned in both the accounts so would advice you to stay away from such a practice
If your Adsense is account is on good leverl and you're making good money and your website have original content and targeted traffic than you can make more Adsense accounts from your PC
The problem is you don't understand what I wrote, so we could talk like this for a very long time.. One account per person, this I'm ok. I'm talking about managing several adsense accounts in the name of different persons. This you don't have to get paranoid about it. From my computer I log in several adsense accounts for people who are in different countries, I have been doing it for years, there is no problem, and why would there be anyway?