I used to have windows 2000 on HP and upgraded it to XP windows a year ago. As a result of the upgrade, my CD ROM will not read a disc at all. It did not bother me before but now it bothers me because I have a digital camera and I need to download the software with a CD. The CD icon shows up on My Computer and the disc icon even shows up on the screen but it just will not read at all. Help!