I have installed hp combo 535, it reads windows xp for booting only. It cannot read cds/dvds. even explorer does not show contents.

SOURCE: Can read cds but not dvds

Try this, but if the problem persists, you need to replace the drive. Go to my computer>properties>hardware>device manager and look down the list for your cd/dvd drives and click the '+' sign then highlight your dvd drive and right click to delete. Restart the pc and windows will find the drive again automatically and install the drivers.

SOURCE: Windows XP not recognizing cds/dvds in my HP DVD640i

Most likely your CD-DVD burning software is corrupted. When that happens, the machine doesn't recognize the existence of the CD/DVD hardware. Clean up your machine, defrag, run a freeware registry cleaer-defragmenter (see C-net for a good one). Then Reinstall/upgrade your burning software (the Windows XP software is not sufficient) either from HP/Compaq, if it came with your machine, or the program website if you purchased it separately. You may find out which it is by using a marvelous freeware program called Belarc advisor.

SOURCE: comdo fail to read DVDs'

1. Check its DVD reading speed
2. Try reading a prerecorded or original DVD disk for a movie for example, if it can read this then it means the DVD you are tryng to read were burnt at speed faster than what your DVD can read.

SOURCE: my dvd rom is not able to read CDs..but it can read DVDs..help me

i have my dvd drive problem
it is not reading any cd

SOURCE: hp CD\DVD rom not reading CDs, but is reading DVDs?

cd/dvd rom is probably not working ,try using a lense cleaner disc if that doesn't work it's cheap enough to just install a new drive DVD/Rw as they are about £20.00 new.