I am on my 3rd ps2. My first went through the same things. Loading times, not playing certain games or dvds, etc. I got a second one and it lasted about 4 months. It took a fall and decided to no play any games anymore. But after that I voided the warranty on my 1st ps2 and boy oh boy was it full of dust. I cleaned it out and it worked fine for a couple more months. I bought a third and it has worked fine.
The first models were of lesser quality as Tiger said. There have been at least 4 versions made. With that said though the first X-Boxs also had a flaw but not as serious as the first PS2s. But this should teach everybody to buy a warranty

I did after my third one