Windows XP not recognizing External CD ROM

O.K., I’ll do my best to explain this. I’ve been having trouble booting into Windows XP. Tonight I managed to get in in the safe mode. Not knowing how to get out of the safe mode, I performed a system restore from a recent day when I was able to get into XP. Unfortunately, when XP booted, Windows did not recognize my external CD ROM. Did the restore remove the Windows driver(s) for the USB ports (it’s a USB CD ROM DVD unit) or the drivers which are necessary for Windows to recognize USB hardware and for me to operate it? If so, are there files I need to download, and, if available, where might I find them? Thanks in advance…