I'm going to assume that you don't want to have to re-install Vista and all your apps ....along with hours and hours of tweaking to get things right...
That being said here's how i'd approach it.
(Keep in mind some of these suggestions are simply precautions)
1) Assemble all new and existing drivers and have them in one place...preferably on 1 cd but not neccessary.
2) Backup all browser and e-mail info...if using FireFox MozBack will do both FireFox and Thunderbird...great app.
3) If you do have an image app do a backup of your existing system and burn it to CD/DVD just in case.
----------------
4) Leave the new HDD out of the equation for now. We are going to work with the existing one. Replace the PSU.
5)Then replace the CPU...making sure to follow the install info provided and apply thermal compound properly.
Thermal Paste Guide6) Leave the new RAM go for now as well...we want to boot to Vista with the least amount of changes.
7) Power up...chances are Vista will not hiccup with just the CPU being swapped. If it doesn't take the time to check all is well especially in Device Manager. If so we'll continue...if not:
Repair Install of Vista.I suggest a full read and a printout for reference before starting...if this step was not needed with the CPU swap then we're almost done.
8.) Re-boot after checking all is OK with the CPU swap and then power down.
9) Install the vid card.
10) Boot up...Vista will detect the card and want to search the web for drivers for it...don't let it. Point the install to the CD that shipped with the card instead and install that way. Re-boot...and again check all is OK in Device Manger.
(
At this point most are tempted to tweak the vid card...forget that part for now...you will have time.)
11) Add your new RAM...make sure to check the MBoard manual for slot configurations etc. Re-boot a few times and make sure all is well.
-----------------------------
When you are satisfied you have arrived here and before tweaking now the important step.
Power down. Hook up the new HDD as a slave drive. Boot to the HDD manuf. CD that shipped with the drive...if it didn't DLoad the Free utilities from the NEW HDD manuf. site. Follow the info to create a bootable CD.
Boot to the CD and open the Utility program...most autorun.
Choose the "clone" selection and "clone" the old drive to the new one. When it finishes power down...( DO NOT interrupt this process for anything.)
Remove the original drive completely and hook up the new drive as master with the correct jumper settings or SATA connector on the board.
Power up and you are now on your new setup.
Tweak to your hearts content...after tweaking burn another image of the new drive...then you can hook up the old drive as slave...format and use it for storage.
Congrats on your new Upgrade ! !