What is Windows 7 RC

[LetsC]

Hi,
I am quite a noob but I really want to know about it. I want to upgrade from windows XP to windows 7. Please help me understand windows 7. which 1 is the best & i should prefer. I just want to test the OS & have a walkthrough.
What do you guys mean by build 7106 was leaked in china?

[RockON!!]

Hello friend.

The Windows 7 RC is no longer available for download. If you’ve got the download and need a product key, they’ll be available until October 21, 2009.

To look up your product key or get a new one, just go through the steps like you're starting a download.
Getting ready to install the RC? Read this first

Here's what you need to know before you get started:

• Installation: If you are running Windows 7 Beta you'll need to back up your data (preferably on an external device) and then do a clean install of the Windows 7 Release Candidate. Then, you'll need to reinstall applications and restore your files. If you need help, please see the Installation Instructions.
• Tech details/updates: before installing the RC, please read the Release Notes and Things to Know for important information about the release.
• Routine news: For day-to-day news, keep an eye on the team blog. And, you can get non-technical news, tips, and offers by subscribing to the monthly Exploring Windows newsletter.
• Back up your data: We know you know this already, but please back up your data and please don't test the RC on your primary home or business PC.
• Keep your PC updated: To get critical updates, be sure to turn on automatic updates in Windows Update.
• Remember expiration dates: Please plan ahead for when the RC expires. You'll get two weeks' notice, and then beginning on March 1, 2010, your PC will start shutting down every two hours. The RC will expire on June 1, 2010. To avoid interruption, you'll need to rebuild your test PC to replace the OS with a valid version of Windows, and reinstall all your programs and data before the software expires.

[GianCarlo]

Looking good, I have so many programs to refuse to work with Vista & Xp mode helps me. Is there something for windows 7 too? I have also heard Vista and Win7 have a very similar functionality if you prefer the mouse over the shortcut I mentioned.

[envo diverter]

I know that the downloads are not available now but what about installing I have the copy from my friend. I need the serial key.

Is it possible to install & still activate it? Or do I have any other option available? Should I buy it?