I've tried two ways to install Ubuntu!
The one that I used more times, is via bootable usb drive! I've downloaded the iso from the authorized site!
I have a 500 GB HDD and I've partitioned it firstly in 2 partitions one with my Windows 7 OS and my programs and another with my media, files, etc.
Then I took free space (25 gb) from the second partition and i made it free space.
I installed Ubuntu 13.04 via the usb stick using 18gb from the free space for the Ubuntu OS using mounting point of "/" formatted as "Ext4".
I also used 8192 gb of my free space for swap!
The installation completed successfully but after the reboot I am not shown the options to choose which OS to use and windows start automatically.
I've also tried to find the partition in the boot menu but it is not visible even there! I did the same thing 5-6 times with the same result!
The second way that I tried to install Ubuntu 12.04 Lts was via windows installer! I installed it on a new partition this time, because I don't want to have Windows 7 OS and Ubuntu OS in the same partition, and at the end of the installation an error message appeared. I pressed "OK" and then my PC rebooted again!
Please can you take a look at the methods I used above and tell me where I am going wrong, especially for the 1st method of installation?