I purchased a refurbished D630. It came with XP installed and Internet Explorer. It also had a Microsoft Security Antivirus. I downloaded the Free AVG and also Fire Fox. The laptop would shut down or start up by itself. I returned the laptop and was told that there was a ton of conflicting software and that I should not have more than one browser on the laptop. I also have a Latitude D810 with Fire Fox, Google and Fire Fox and have no problems. Why would the D630 not be capable of handling more than one browser downloaded? The A/C adapter also has been cut in several places. I thought that the adapter probably caused the problems.