You can simply install linux on your computer with preinstalled windows vista by following the simple step by step process listed below.
Step by Step Procedure To install Linux With Vista
1. Boot in Vista and go to – right-click My Computer>>Manage>>Disk Management.
2. Right-click on the main Vista partition and select Shrink Volume.
3. Enter the shrink size and it will reduce the volume of the primary partition, leaving the rest of the disk free as unpartitioned space.
4. Now Boot Up with Linux setup cd or dvd and simply install linux on the new unallocated partition.
5. That it. As you will see entry of vista in the default bootloader of linux by slecting that you will be able to boot vista with no problems.
If You have any problems in following the procedure below leave a comment here.