120GB PS3?’s

So I just got my new 120 GB PS3 system today. So far I am happy with this system. But I have a question about something that is bugging me a bit. I inserted the USB cable that comes with the PS3 system and charged my SIXAXIS DUALSHOCK 3 and everything up to now works perfect. But after my SIXAXIS DUALSHOCK 3 was charged I turned the PS3 system off to remove the USB cable from the SIXAXIS DUALSHOCK 3 and PS3 system. I was able to take the USB cable off my SIXAXIS DUALSHOCK 3 with no problem but I need to hold my system down to remove the USB cable from it, as I moved my system when I just tried to take the USB cable off without holding it. Is this a problem or defect with my PS3 system or USB cable that was put in with my PS3 system? Has this happened to anyone with the PS3 system? Also I do not understand why I cant register my new PS3 system on the PLAYSTATION website? Any information and/or help with my questions will be great. But so far my 120GB PS3 is #1. I had the Nintendo Wii and XBOX 360 systems and I was not as happy as I am with my new PS3 system. YES $299.99 is a lot of cash for most people (Like Me) to spend on a video game system but the PS3 system is more then just a video game system.