It appears that there is a very serious bug which will affect users of Windows 7 and Windows Server 2008 R2.

This vulnerability affects SMB (Windows Server Message Block) this is the part of the system which deals with Network resources such as access remote printers and access to remote computers.

Microsoft confirmed that currently there is no fix for the problem. Only one solution is to disable SMB and await for update from Microsoft.

Apparently this attack can be performed even if on the machine firewall is enabled.

more informations on author blog.

There where reports that there was a problem with upgrading Vista to Windows 7, but after Microsoft investigation it turn out that this was not a problem but lack of proper preparation on end user side.

Basically you can not upgrade Vista 32 Bit version to Windows 7 64 bit version. If you purchase by mistake or wrong advise Windows 7 64 Bit upgrade for Vista 32 Bit, you should contact shop where you purchased it and replace with 32 Bit version.