How do I install lion on a macbook pro that has a MBR instead of GUID.

Question

Not sure how that happened. Maybe when I installed parallels and Windows XP, but Lion apparently requires a GUID partition. I've backed up and copied all important files to an external drive. If I reformat the drive for GUID how do I restore Leopard so I can then upgrade to Lion. I lost me original disks. Can I make a boot disk from the current OS?

Answer 1

As you know you must install OS X on a GUID partitioned, Mac OS Extended, Journaled drive. You do not need to reinstall Snow Leopard in order to install Lion if you have a copy of the Lion installer. If you don't have a copy of the installer then I suggest you re-download Lion but save the installer on your external drive. Here's how you do that:
Download Lion Again Without Installing Snow Leopard First
There's an easy method to force a download within the Mac App Store without any tinkering. It seems to be the official method, although I found no description of this in any of Apple's documentation.
So here's how to do it:
Open the Mac App Store.
Navigate to your Purchased page.
Hold down the Option key on your keyboard and click on your 'OS X Lion' purchase link (not on the 'installed' button).
You see the Lion product page. It should say 'Installed,' but that button is clickable. Hold down the Option key again and click on 'Installed.' If you don't hold the option key it will tell you there's already a newer version installed.
Enter your login credentials.
Download.
It's important to hold down the Option key twice. Once on the Purchased page, once on the Lion page. You also can't navigate to Lion directly, you need to open it from the purchases page. But if you follow this procedure you should find the Lion Installer within your Applications folder.
Now, make yourself a bootable DVD or USB flash drive for installing Lion:
Make Your Own Lion Installer
1. After downloading Lion you must first save the Install Mac OS X Lion application. After Lion downloads DO NOT click on the Install button. Go to your Applications folder and make a copy of the Lion installer. Move the copy into your Downloads folder. Now you can click on the Install button. You must do this because the installer deletes itself automatically when it finishes installing Lion.
2. Get a USB flash drive that is at least 8 GBs. Prep this flash drive as follows:
Open Disk Utility in your Utilities folder.
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.
Under the Volume Scheme heading set the number of partitions from the drop down menu to one. Set the format type to Mac OS Extended (Journaled.) Click on the Options button, set the partition scheme to GUID then click on the OK button. Click on the Partition button and wait until the process has completed.
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.
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.
Click on the Erase button. The format process can take up to several hours depending upon the drive size.
3. Locate the saved Lion installer in your Downloads folder. CTRL- or RIGHT-click on the installer and select Show Package Contents from the contextual menu. Double-click on the Contents folder to open it. Double-click on the SharedSupport folder. In this folder you will see a disc image named InstallESD.dmg.
4. Plug in your freshly prepared USB flash drive. You are going to clone the InstallESD.dmg disc image to the flash drive as follows:
Open Disk Utility.
Select the USB flash drive from the left side list.
Click on the Restore tab in the DU main window.
Check the box labeled Erase destination.
Select the USB flash drive volume from the left side list and drag it to the Destination entry field.
Drag the InstallESD.dmg disc image file into the Source entry field.
Double-check you got it right, then click on the Restore button.
When the clone is completed you have a fully bootable Lion installer that  you can use without having to re-download Lion.