I have an account that was opened in 2003 but paid off in 2006 but shows slow pay. Is it best to leave it or remove it ?

 

Also, I bought a car in 2/2010 my credit scores at the time were all in the 650 range but now they have all dropped into the 550-600 range is this due to the number of  of inquiries that were done trying to get financing they appartently sent application to every finance company available, because inquiries on that day show to be about 10.   

 

I worked so hard to get it into the 650′s shooting for my 700′s  i am just devasted that it was that easy for someone to bring me down. Â