I do not think I have one and I wanted to back up my music and other files into 4.7 GB DVDs. What should I do?

Windows XP Home Edition Service Pack 1
2.67 gigahertz Intel Pentium 4
8 kilobyte primary memory cache
512 kilobyte secondary memory cache
79.97 Gigabytes Usable Hard Drive Capacity
62.03 Gigabytes Hard Drive Free Space

_NEC DVD+RW ND-1100A [CD-ROM drive]
JLMS DVD-ROM XJ-HD166 [CD-ROM drive]

WDC WD800BB-75FRA0 [Hard drive] (80.00 GB) -- drive 0, s/n WD-WMAJD1879815, rev 77.07W77, SMART Status: Healthy
RADEON 9800 SERIES [Display adapter]
RADEON 9800 SERIES - Secondary [Display adapter]
MAG 16.1 [Monitor] (16.1"vis, June 1997) (2x)

The Broom, are you saying that if I just take the DVD - R disks back to the store and exchange them for DVD + R, it should work?
Rajinder, I do not understand your answer at all.
Siddanth, when I put the DVD-R disk in my tray, my pc did not react at all and Musicmatch seems to think the dvd is a cd with only 78 minutes capacity!!