My Graphic Card was perfect when i play games now is freezing,skipping frames, bad visuality.

My PC Get Slowed I use my pc 2 years nothing happened any slows etc.. it was very fast and clean computer but until now I play games like LoL(League of Legends) Pes 2013 I format my Computer and download LoL(League of Legends) nothing happened I played about 4-5 months something and when im bored I decieded to download Pes 2013 after 2-3 days im played pes 2013 when im opening pes 2013 my pc get slowed like a hell I cant even watching youtube cause its skipping frames, freezing when im watching and also its effect the LoL(League of Legends) too, I cant even play LoL cause my graphic card and visuallity gets worse my champions in the game cant even move when im click somewhere in the game its moving after 5 seconds like a slow motion when I typing something in the game its appear after 5 seconds, if u ask me ur internet speed limit reached or slow NO! my internet speed is fast and I check I didnt reached my internet speed and also this happened Pes 2013 too and without internet, and also when im searching something in the internet(I use Google Chrome) when im typing something its appear after 5 seconds too slow cant even search something. And I have ESET NOD32 ANTIVIRUS 4 I bought it Licensed version, Not cracked or downloaded from somewhere, I bought it and its licensed valid until 2014.When im restart my computer its going to normal but when im going to YouTube or play games again my pc starting to slow, freezing, skipping frames and responding late on visuallity, I think my graphics card have issue I dont know why this happened to me everything was ok after im downloaded Pes 2013 and then I played, after this happened to my pc, I format my pc and install all updates then I install LoL(League of Legends) and Pes 2013 again, I played both of the game nothing happened it was good no freezing, no skipping frames, visuallity was perfect and also when im watching youtube no freezing too it was clear visuallity but after 2-3 days again this issue happened too me again my pc getting slowed, and in the games again freezing, frame skipping late responds slow motion game, and after that I format my pc again for last time this time I didnt install pes 2013 I deleted pes 2013 from my pc I only install the League of Legend this time nothing happened but this time after 1 week again I got same issue for now again bad visuallity, freezing, slow pc, frame skipping, late responds in the game and also in the Google Chrome web browser,I dont know what makes my pc slow and effect my graphic card for bad visuallity and keep freezing in the games and frame skipping in youtube. I learned that when im format my pc everything get normal but after 1 week again this issue starts. Any suggestion to this issue please reply my system requirements on the below:
Operating System: Windows 7 Ultimate 32-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_gdr.130318-1533)
Language: English (Regional Setting: English)
System Manufacturer: HP-Pavilion
System Model: FT966AA-ABG s3780a
BIOS: Phoenix - AwardBIOS v6.00PG
Processor: Intel(R) Core(TM)2 Duo CPU E7400 @ 2.80GHz (2 CPUs), ~2.8GHz
Memory: 4096MB RAM
Graphic Card name: NVIDIA GeForce 9300 GE
Manufacturer: NVIDIA
Chip type: GeForce 9300 GE
DAC type: Integrated RAMDAC
Display Memory: 1648 MB
Dedicated Memory: 241 MB
Shared Memory: 1407 MB
Current Mode: 1920 x 1080 (32 bit) (60Hz)
Monitor Name: Generic PnP Monitor
Monitor Model: ASUS MS236
Monitor Id: ACI23F4
Native Mode: 1920 x 1080(p) (60.000Hz)
Output Type: HDMI
Driver Name: nvd3dum.dll,nvwgf2um.dll,nvwgf2um.dll
Driver File Version: 9.18.0013.1422 (English)
Driver Version: 9.18.13.1422
DDI Version: 10
Driver Model: WDDM 1.1

And I also open my pc inside and cleaned the dust and also the Graphic Card when im open my computer after that I opened League of Legends and it was perfect everything comes normal no freezing, no skipping frames, no bad visuallity, no lagging but after 5-10 minutes in the game again the issue starts I dont know what is the problem.