I have two HDD's in my computer, can I transfer data to the HDD without Vista installed on it and reinstall Vista? Will I save my data this way?
Yes, Data files only of course, no programs. You can use the Files and Settings Transfer Wizard under Accessories\SystemTools if you like. Just tell it what you want to copy over and pick a folder on the 2nd hard-drive when it asks you the transfer method.
Don't forget your email files too unless you use yahoo or gmail or any online email app. then don't worry.