Optical drive picks and chooses when it will work

Question

For some reason, the optical drive on our Mac has been acting weird for about 3 months. It will only read my husband's games (Civ IV and Command and Conquer). It won't read any of our kids' games, my CDs, or any of our backup CD-Roms. It also won't burn any CD-roms. I haven't checked recently, but a couple of weeks ago my 7 y.old was watching Harry Potter on it, so I guess the DVD function still works.
I'm assuming that we need a new drive. Space on my desk is at a premium, so I'd like to find something internal rather than external. I don't burn disks very often--usually just backup disks and photos a few times a year. We don't burn DVDs, at least not yet!
Is my hypothesis correct in that the drive is kaput? If so, what should I look for in a new drive? Are there any especially good drives? And is an internal drive a good choice (assuming that external drives come with more bells and whistles)?
I have installed memory upgrades several times over the years , so I'm pretty comfortable working inside a Mac. (Eeep, 1st Mac Love was in 1988 <--dating myself). Is this a job that I could do myself?
Any help is welcome!
Thank you--
Jane Healy
Machine information:
PowerMac G4 with dual 867 MHz processors, 1 MB L3 cache per processor, 1.75 GB DDR SDRAM and using OS 10.4.9.
Here's the info on the drive:
PHILIPS CDD5101:
Firmware Revision: A4.2
Interconnect: ATAPI
Burn Support: Yes (Apple Shipped/Supported)
Cache: 8192 KB
Reads DVD: Yes
CD-Write: -R, -RW
Burn Underrun Protection CD: Yes
Write Strategies: CD-TAO, CD-Raw
Media: No
PowerMac G4   Mac OS X (10.4.9)  

Answer 1

Sure sounds dead to me. If it won't play or record at all, that's a very bad sign. The lens cleaning trick may work, but you should have noticed a lot of skipping before it got to the point you are at now if it was just the lens. But that's definitely what you want to do first, to be sure.
Installing an optical drive is not difficult. OWC has a great series of videos on how to do so at this link: http://eshop.macsales.com/tech_center/installation.cfm
Pioneer drives are very popular with Macs and for good reason. The current version is the 112, and has received generally good reviews (OWC carries the 112, although New Egg has a cheaper price. Both are bare drives - not retail versions, but you can just reuse the screws and cables you have). xlr8yourmac maintains a user database of people's experiences with different drives in different machines at this link:
http://forums.xlr8yourmac.com/drivedb/search.drivedb.lasso
It's an excellent source of info. If you want to go with a retail package, it will cost more. Best Buy carries the 112, but Pioneer gives it a different number in the retail version (it's the 1810).The retail package will give you some windows software and screws and a cable. Now that I think of it, I don't know if your machine has a 40 or 80 wire cable; you'd need the latter to get full dvd burning speed from the drive. If you want to go external, I just got a Samsung 184 and it works beautifully, on sale at Best Buy but sale ends today. A combo drive like the Philips will only run about $10 cheaper than a dvd burner.
Look to spend about $40 for a bare drive, $65 for a boxed version, $80 to $100 for an external.
mac pro, dual 1.25 g4   Mac OS X (10.4.9)   dell 9200, dell xps 400