Windows 7 Freezing Slow Response

My lap top is only 2 month old, I have kept it in great condition, not downloading tons or random movie and music files. It has been running perfectly. It is a Windows 7 HP Probook 4530s.Today my friend and I were downloading Java to play minecraft. The download went ok, and I proceed to boot up the minecraft program. When the program loaded the computer began lagging horribly. I quickly ended the program and attempted to restart it, the program ran with the same horrible lag.So I ended the program, but my computer was still lagging, all programs I attempted to run took for ever to start up, and when they did they froze. I restarted the laptop and after all the programs started up, I attempted to run Firefox, and it loaded, then froze, as did all other programs, I had to force the computer off. I spent the rest of the day cleaning up the computer, deleting old program files, music, I ran multiply disk clean ups, and attempted to defrag the hard drive. But these programs all froze.I restarted and ran in Safe Mode, and it worked fine, all the programs loaded and nothing froze. Me and my friend worked on it all day, finally we found out that the Minecraft program had installed wrong, or something like that, THe program files were installed in the wrong place. We deleted those file and restarted the computer. It started up, and All programs functioned for a while, and the lag was gone, it all ran smoothly, then maybe two minutes later everything freezes.