Booting from the Windows 10 media you create will present these options.
Because there is no upgrade path from Vista to Windows 10, you won't be able to preserve apps and settings.
Custom install will give you option either erase the existing hard disk or select a drive or partition where you would like to install it. Because Windows 10 is still a preview, it is strongly recommended if you wish to evaluate it, you should do so on a partition.
create a partition and install the Technical Preview there:here is how you create a partition in Windows 7 or Vista:
Open a Run command (Press Windows key + R) on your keyboard. Then type diskmgmt.msc then hit Enter on your keyboard.
Alternatively, you can click Start, right click Computer > click Manage > click Disk Management.
Once Disk Management is open, select the C:\ or where Windows 7/Vista is installed.
Right click it and click Shrink menu.
Wait while Windows Vista.7 checks for available disk space.
Enter the amount you want to allocate. Depending on the architecture of Windows 10 you want to try. If you are using Windows 10 32 bit, you can allocate 16 GBs or 20 GBs if you using the 64 bit version. Another factor is disk space for applications, page file and drivers.
Click OK.
The Disk Management window should display unallocated disk space.
To learn how to change your BIOS options to boot from the DVD drive, see the following tutorial:
http://notebooks.com/2011/05/05/how-to-load-bios-and-change-boot-configuration/
Once your computer is set to boot from the DVD, you should see this option.
The Windows logo will appear on screen, this might be here for a while, as long as your see the indicater, everything should be ok.
You should now arrive at this screen, select your time and currency format then click Next.
Click Install Now
Wait while setup starts up
Accept the End User License agreement and click Next
Click Custom install Windows only (advanced)
Click Next and wait while the preview installs.
