NEED HELP! BAD GRAPHICS... :(

Hey guys, I recently just built a computer and had to buy a monitor, mouse, and a keyboard (irrelevant) but the first graphics card I got ended up malfunctioning so nvidia decided to replace it for free and I got the same one and it is working fine. The only problem is that I feel like the graphics aren't as good as they should be... When I watch videos, any type of videos, youtube, movies, anything, the graphics are bad and the shading and texture looks pixely... I know its not the quality of the video because I can watch them in 1080p hd, and on my 5 year old laptop the graphics are better... So please, if you guys have any suggestions that I can do to fix the bad graphics then please let me know! this is frustrating cause I spent around 900$ on this computer and it isn't up to par... My specs are bellow. Thank you  

GPU - EVGA GeForce GTX 480 (Fermi) 1536MB 384-bit GDDR5 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card - http://www.newegg.com/Product/Product.aspx?Item=N82E168...

CPU - Intel Core i3-2120 Sandy Bridge 3.3GHz LGA 1155 65W Dual-Core Desktop Processor Intel HD Graphics 2000 BX80623I32120 - http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Hard drive - Seagate Momentus XT ST500LX003 500GB 7200 RPM 32MB Cache 2.5" SATA 6.0Gb/s Solid State Hybrid Drive -Bare Drive - http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Opti - LG Black 10X BD-ROM 16X DVD-ROM 48X CD-ROM SATA Internal 12X Internal Blu-ray Drive 3D Playback & M-DISC Support Model UH12LS29 LightScribe Support - OEM - http://www.newegg.com/Product/Product.aspx?Item=N82E168...

RAM - G.SKILL Ripjaws Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model F3-12800CL9D-8GBRL - http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Mother Board - BIOSTAR TZ77B LGA 1155 Intel Z77 HDMI SATA 6Gb/s USB 3.0 ATX Intel Motherboard with UEFI BIOS - http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Monitor - ASUS VS Series VS238H-P Black 23" 2ms HDMI LED Backlight Widescreen LCD Monitor 250 cd/m2 50,000,000:1 - http://www.newegg.com/Product/Product.aspx?Item=N82E168...

PSU - OCZ ModXStream Pro 700W Modular High Performance Power Supply compatible with Intel Sandybridge Core i3 i5 i7 and AMD Phenom - http://www.newegg.com/Product/Product.aspx?Item=N82E168...