Need help with advanced partitioning during installation

Hello guys

I want a detailed walk-through of how I should go about installing Linux on my system. None of the basic guides I found on internet cover this , hence I am posting here.

I have an Athlon II X2 260 3.2 GHZ, 4 GB DDR 3 Gskill, 500 GB hard drive and Asus Radeon HD 7750 1 GB DDR5 card with suitable PSU.

I have Windows 7 Ultimate SP1 64-bit installed on my C drive (146 GB).

My hard drive partitions are as follows C drive 146GB , D drive 146 GB and E drive 172GB. I want to partition D drive into sizes 70 GB,70 GB and 6 GB during installation for use of UBUNTU 12.04 Desktop Edition LTS Linux. I want to setup the first 70GB partition for Linux installation , next 70GB for Data and the next 6GB for Swap file.

But I don't know how to go about doing this. The last time I installed UBUNTU choosing 'Install alongside Windows 7' option and default settings for partition I was unable to boot to Windows 7. I have vaguely heard something about UBUNTU not being able to detect MBR if windows C drive partition is above 100GB. Is this the cause for my windows being unable to boot ?

I want to learn Linux and I am an absolute beginner. Can you kindly guide me to install Linux on my Drive or give me an link to appropriate trustworthy documentation resource.

Thank you for your time.

Xarin.