Let me clear something up really quick for everyone.
Tom's does not tolerate let alone condone piracy of any kind.
However, when we're talking about Microsoft Windows; the copyright works a little differently. Windows comes with a 30 day trial. Hell, you can even keep using it after the 30 days if you don't mind having no desktop background and getting popups every few hours telling you to activate your product.
Bypassing that activation, is piracy, and copyright infringement.
The copyright on Windows applies to the end user license agreement, or activation. Not the software itself, though the source code is owned by Microsoft.
Think of it kind of like when you're shopping around for anti-virus or a media converter. There's always a free trial, but you have to buy it at the end of the month or a bunch of features won't work anymore. Cracking the activation to avoid paying that fee is illegal, not downloading the software in the first place.
If you already own a copy of Windows and have the key to boot, you can download another copy no questions asked. If your key is no longer valid, though, you will need to buy a new one.
As was said above, avoid downloading them from torrent sites or other peer to peer file sharing services like Limewire or Ares.
These are direct download links from Digital River, one of Microsoft's partners. Please use the one that matches your current installation.
Windows 7 Home Premium with Service Pack 1:
x86 x64
Edit: just realized you specified what version it was, so I've removed the other links.