Upgrade free win7 or 8.1 into win10

Microsoft has rolled out a free evaluation version of Windows 10 Enterprise edition so you can play with it for 90 days if you're still on the fence about upgrading.

On Wednesday, Microsoft officially started pushing outWindows 10 as a free upgrade to Windows 7 and 8.1 users who reserved a copy. The upgrade is free for one year, so if you haven't yet installed it, you have plenty of time to decide whether or not to dive in. The upgrade naturally wipes out your existing installation of Windows 7 or 8.1, though you can roll back if for whatever reason you don't want to stick with Windows 10.

Another option, though, is to install the free 90-day trial of Windows 10 Enterprise edition to check out the new OS.

But if the Windows 10 upgrade itself is free, why would you need to bother with a free evaluation edition? Well, installing the trial version gives you three months to check out Windows 10. During that time, you can still maintain your current Windows 7 or 8.1 environment for your everyday tasks. But -- yes, there's always a but -- the Enterprise edition is geared for large businesses so it doesn't offer the same features you'll find in the Windows 10 Home and Windows 10 Pro editions that Microsoft has been pushing out as a free upgrade.

The downsides? Most of the apps that come with Windows 10 Home and Pro aren't available in the Enterprise edition. So you won't find Mail, Calendar, People, Photos, Cortana or other apps. And the Windows app store isn't available either, so you can't download apps. But despite these limitations, the Enterprise edition at least gives you a taste of Windows 10.