I have a Dell Latitude D620 XP PRO SP2. I loaded AutoCad fine but when I go to start- programs- autodesk- autocad LT 2008- autocad LT 2008 to enter the serial number to register it. It never opens. The hour glass pops up for 2 secs and thats it it never opens. Now I load it on a desktop and it works fine? Help?? Can someone help me? The laptop and desktop have the same os and memory (1gig)memory.