Software for a TV being pictured on my PC

Hello everyone! I have my whole hardware to be assembled this weekend. It consist of 500GB of SATA hard drive, an AMD Liano 3650 processor, and a memory of 4GB RAM and as a basis, I installed Windows 7 64-bit . Now my question is what is today’s best possible software that is fast to get a TV being pictured? Does it need to be connected to a DVB-T Stick? I want to know if an HTPC is mainly for watching TV, high definition video, and YouTube, listening to music, and surfing the net. Optionally, I no longer need the Microsoft’s Windows interface, but it doesn’t mean that I do not have to see anything. I would like it to appear preferably in TV mode, once the computer starts up as soon as possible in the appropriate application, the DVB-T picture is quite blurry and can I adjust the software smaller? Are there any best procedures for this? I need help. Thanks everyone.
