Spooky FF/Chrome Auto-Fill Options

I currently use a computer that I bought off a former coworker of mine. It's a good system; he was using it with Server 2008 for a home business he was operating at the time. Naturally, having no need for Server 2008 it was the first thing to go. I messed around with Win7, then a distro or two of Linux, before eventually reinstalling Win 7 and going on my merry way. In fact, I've done a repair install of Windows since making that final decision.

The thing is...his personal info still shows up in Chrome and FireFox's autofill. That is, when I double click a website's name/address field, one of the options will be his name, his address or his phone number. Since getting it, we haven't had any contact at all, so I know full well he's not touched it to fill anything out. Really, he didn't even have anything other than IE on it when I bought it off him. Browsers have been installed, borked up, uninstalled and reinstalled (as has the OS) a couple times. Still, it'll show. What's weird is it isn't always 100% of the time - some sites will have him as an option, but not others.

This doesn't have any real impact on how the PC operates, but it is about 200% weird and I'd like to know if anyone has any ideas how the heck something like this happens. I mean, that data can't just coincidentally have survived a few OS transitions...could it?

Thanks,

M.