I may be wrong, but there is no "upgrade" path from Vista to Win7. You will need to do a fresh install which is better than a upgrade.
You will loose all your data unless youu have a backup...you have a backup dont you?
Outlook backs up all the info using a pst file. You can backup the pst file using a free microsoft tool click here
Ensure that all your hardware and software are compatible with Windows 7 before you make the jump. Windows 7 upgrade advisor click here will be a good start.
Once youve decided to make the jump and you have all the relevant cd/disk for all the software that you have alook here click here