I assume your existing drive is still installed in the computer, and you have a functioning OS X installed on it.
When you get your new drive install it in an external enclosure - FireWire preferably for speed. Prep the new drive as follows:
Extended Hard Drive Preparation
1. Open Disk Utility in your Utilities folder. After the installer loads select your language and click on the
Continue button. When the menu bar appears select Disk Utility from the Installer menu (Utilities menu for Tiger or Leopard.)
2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Note the SMART status of the drive in DU's status area. If it does not say "Verified" then the drive is failing or has failed and will need replacing.
SMART info will not be reported on external drives. Otherwise, click on the
Partition tab in the DU main window.
3. Set the number of partitions from the drop down menu (use 1 partition unless you wish to make more.) Set the format type to Mac OS Extended (Journaled.) Click on the
Options button, set the partition scheme to GUID (only required for Intel Macs) then click on the
OK button. Click on the
Partition button and wait until the process has completed.
4. Select the volume you just created (this is the sub-entry under the drive entry) from the left side list. Click on the
Erase tab in the DU main window.
5. Set the format type to Mac OS Extended (Journaled.) Click on the
Options button, check the button for Zero Data and click on
OK to return to the Erase window.
6. Click on the
Erase button. The format process can take up to several hours depending upon the drive size.
Next, repair your existing hard drive and permissions:
Repairing the Hard Drive and Permissions
Boot from your OS X Installer disc. After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from the Installer menu (Utilities menu for Tiger and Leopard.) After DU loads select your hard drive entry (mfgr.'s ID and drive size) from the the left side list. In the DU status area you will see an entry for the S.M.A.R.T. status of the hard drive. If it does not say "Verified" then the hard drive is failing or failed. (SMART status is not reported on external Firewire or USB drives.) If the drive is "Verified" then select your OS X volume from the list on the left (sub-entry below the drive entry,) click on the First Aid tab, then click on the Repair Disk button. If DU reports any errors that have been fixed, then re-run Repair Disk until no errors are reported. If no errors are reported click on the Repair Permissions button. Wait until the operation completes, then quit DU and return to the installer. Now restart normally.
If DU reports errors it cannot fix, then you will need Disk Warrior (4.0 for Tiger, and 4.1 for Leopard) and/or TechTool Pro (4.6.1 for Leopard) to repair the drive. If you don't have either of them or if neither of them can fix the drive, then you will need to reformat the drive and reinstall OS X.
Next, clone the existing drive to the new one:
How to Clone Using Restore Option of Disk Utility
1. Open Disk Utility from the Utilities folder.
2. Select the
destination volume from the left side list.
3. Click on the Erase tab in the DU main window. Set the format type to Mac OS Extended (journaled, if available) and click on the Erase button. This step can be skipped if the destination has already been freshly erased.
4. Click on the Restore tab in the DU main window.
5. Select the
destination volume from the left side list and drag it to the Destination entry field.
6. Select the
source volume from the left side list and drag it to the Source entry field.
7. Double-check you got it right, then click on the Restore button.
Destination means the new drive.
Source means the existing drive.
Test your clone to be sure it will boot the computer. Restart the computer and after the chime press and hold down the OPTION key until the boot manager screen appears. Select the icon for the external drive and click on the downward pointing arrow button.
If your clone works OK, then you can swap the drives. After you successfully boot the computer with the new drive installed open Boot Camp Assistant and create your Windows partition. Then restore your Windows system with whatever software was used to make the backup.
