2 Steps Forward - 1 Step Back

I always have my eye out for new applications that'll clean and peed up my computer. Today I downloaded "XP Repair Pro" and "PC Pit Stop Optimize". I ran them both, they cleared a few problems, cleaned my registry and appeared to have made my computer a little more efficient. However now when I went to YouTube, it won't play. Now I gotta look into why and what I did differently from yesterday to cause this BS. It's always something, I'll tell ya!