Windows 7 Suddenly Not Responding?

Yo people. So it was a regular day, found a program online and created a restore point before installing... suddenly about two hours later while surfing the interweb boom!! Internet Explorer stop responding so I think "it's not so bad... it happans timw to time" but the only differents is that the message doesn't pop up, like windows doesn't even relize it! But continuing on, I right click on the taskbar to start task manager because clicking the exit button fails the taskbar AKA explorer.exe caught the same flu as IE. So now I can touch the taskbar so Ctrl+Alt+Del is left... screen turns black as always when I do the keystoke but it stays black. So I shut off my computer. Start-up was a little more slow and worked fine before I open IE and it starts all over again. I try restoring, scanning (later with various other antivirus) nothing found, memory test (normal), and everything else like uninstalling unused programs and fixing the registry with Registry Repair. I got Startup Delayer which helped with the slow Start-up but nothing eles. But sometimes like 1/5 times my computer boots up and i perfect like before but when I turn it off it happens again on the next start-up