It was for me. On my system, I have two hard drives. C: has Vista & the other is divided into two partitions M & X. M contains all my media with the exception of recorded tv, which is the logic for partitioning x drive I.e. because recorded tv files are largeish & are added & deleted regularly, I decided to let it be the fragmented partition. So when I stuck 7 on X, I just copied the tv files over to C & installed it there as a separate os on a separate drive.
The copy I downloaded was an iso, burnable to dvd via nero or similar, but I found I could extract the files with winrar & install form there. When I got rid, I used disk management to format the drive & a utility called bcd editor to remove the mbr record so that I stopped being given the dual boot option on start up - That is to say the in Vista, the boot.ini file is replaced by bcd.
Bcd editor is a utility to edit that file in a gui format rather than command line.
Quick cc clean & defrag & back to normal.