Windows 7 users: Move to SP1 to continue receiving Microsoft support
Summary: The end of support date for Windows 7 without Service Pack 1 installed is April 9, 2013.
The end-of-support date for Microsoft's Windows 7 -- without Service Pack 1 installed -- is quickly approaching.
Windows 7 RTM (release to manufacturing), with no service pack installed, will no longer be supported as of April 9, 2013, according to a February 14 post on the Microsoft Springboard Series blog. Support for specific Windows releases ends 24 months after the release of a new Service Pack, and Windows 7 SP1 was released in February 2011.
Windows 7 SP1 mainstream (free) support continues until January 13, 2015. Extended (paid) support for Windows 7 SP1 is available until January 14, 2020. (Microsoft continues to provide security updates for free during the Extended support phase of a product.)
The Springboard blog included this chart to explain the differences between Mainstream and Extended support:

As far as we know, Microsoft has no plans to release a second service pack for Windows 7. Many of us Microsoft watchers have asked the company about this but received no comment. Microsoft is believed to be moving to a new model, via which it delivers annual refreshes of Windows, rather than big-bang releases once every three years or so, with service packs delivered in the interim.
The new model will likely change policies for some IT shops that have waited until Microsoft ships SP1 of a new version of Windows before even considering to move to the latest release.
The Office division at Microsoft seems to be on a path of sticking with the Service Pack model for the foreseeable future.
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Talkback
Why would anybody using Win7 be running without SP1??
Seriously, why in the world would anybody be running without SP1???
Support should be terminated sooner rather than later.
Then you can pay for my copy of Windows 8
Windows 8...
And
Installing Window 8 ?
I agree with @spdragoo
That is an absurd position....
In fact, just today, I was approached by a large manufacturer to try to extend the life of the control system that they are using by maybe three more years or so. To put it into perspective, that OS, while not something that runs on a standard computer is roughly 25 years old. They need to protect the investment they have made.
Just because you CAN do something, doesn't mean you SHOULD do it....
Metro
Impossible on a whole lot of 64-bit.
Errors installing SP1 on 64-bit
Check the Microsoft Answers forum Windows 7 section
Microsoft fail
Errr....
64-bit
So....
I have installed SP1 on maybe a dozen systems and yet to find a problem.
May not be the same reason but whe SP3 for Win XP came out many failed. There were two reasons. First some dumb mistake by [I think] HP where some AMD driver was some how in an Intel system [if I remember right]. The more serious problem was that many SP3 updates failed because lingering malware was on the system - in most cases even though the malware was removed, something in the system that had malware coding blocked the update. See also: http://ebraiter.wordpress.com/2010/03/03/updating-microsoft-windows-and-blaming-microsoft/
I think the no SP2 rule is foolish
agreed
SP2?
I've asked a Microsoft Specialist but hasn't got back to me.
Recently I tried the Microsoft "way" in building an image. SP1 already integrated. Add every update I have related to Windows [550 of them!] and the final image would not fin on a 16GB USB key. One problem is the \windows\winsxs folder. That's were backups to updates installed are stored. Microsoft says if you tinker with that folder, they won't support the system. Too much can go wrong.
and the Chrome OS - the next wave?