I bought a compaq presario C304N with XP pre-installed but, it had Vista as an upgrade sent to me. After instilation I realized I didn't have enough memory to run vista and my computer doesn't work so well anymore. I do have the recovery CD but, I never learned how to do a CD back-up and only copied 15 out of the 90 disks it said it would take (I know I'm not an expert). Is it too late to make a back-up to downgrade? What exactly is the recovery CD? Since my upgrade I can't play any sounds why not? I appreciate any help as this has not been very fun, I just want XP back as it worked perfectly before. I do have I think about 40 GB stored of a hard drive back up of my old files and settings is this useable?