There are lots of request from the readers like whether they might be facing any issues while installing Windows 7 RTM Ultimate x64.
The answer is If you have vista enterprise you can only upgrade to 7 enterprise.But just try this workaround
Basicall upgrade Windows Vista Enterprise to Ultimate (not enabled by default) so Before inserting the Windows Vista Ultimate CD Go to, Start, Run: and type: regedit.exe Go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion
Change the key : ProductName from “Windows Vista ™ Enterprise” to “Windows Vista ™ Business”
Change the key: EditionID from “Enterprise” to “Business”
Pls do not restart Now insert Windows Vista Ultimate CD and start upgrading ..Good Luck