I'm having an awful time trying to be able to play videos. I've installed MPlayer and Xine, but niether of them can play videos. That Mpeglib thing doesn't work either. I can usually hear sound (not from xine), but all I get is a black screen. The same goes for dvd's. Can I configure Mplayer to use something to play videos/dvd's? I'm so confused that I don't know where to start.

Well, do you have all teh pre-requisites for playing DVD's, at least for Mplayer you need libdvdcss, and as for libdvdread it provides its own libkit regarding this issue.

What are you trying as far as the command for Mplayer goes?

Try this if you haven't:
mplayer -vo xv -dvd 1

This does assume your distro made proper symlinks for you..

Cool

Did you install the proper codecs?

win32codecs
Divx
ffmpeg comes with mplayer unless you're using the cvs and I believe xvid is also included.

Thanks- I downloaded the libraries and recompiled with gui support. Then I got the videos to play (just some regular mpegs of my fav. band ).

Now I have a different problem. When I choose any sound driver (OSS seems to work best) the video becomes extremely slow and sometimes the sound gets 'hiccups'. Then I get a message telling me my system is too slow to play that file. It gives me tips, but the ones I tried don't work. I've tried -ao sdl and stuff like that, but they don't help. I know my system is fine, I have a SoundBlaster Live! that works fine with everything else- AMD Athlon XP 1800 CPU, 512 RAM. What could be the problem?

Actually libdvdcss isn't totally required as mine works fine without it.

Well, I kinda got Mplayer running now after messing with hdparm. When I try to play a dvd in user mode, I get this error:

Linux RTC init error in ioctl (rtc_irqp_set 1024): Permission denied
Try adding "echo 1024 > /proc/sys/dev/rtc/max-user-freq" to your system startup scripts.
Using usleep() timing
Can't open input config file /home/zander/.mplayer/input.conf : No such file or directory
Can't open input config file /usr/local/etc/mplayer/input.conf : No such file or directory
Falling back on default (hardcoded) input config

Playing DVD title 2
libdvdread: Could not open device with libdvdcss.
libdvdread: Can't open /dev/dvd for reading
Couldn't open DVD device: /dev/dvd

Can someone tell me what this means and how I can make it work? Thanks.

Yeah, libdvdcss isn't mandatory but it is helpful to have under the belt, as for you problem, does the /dev/dvd exist and point to the right device? Is the actual device has permissions set to allow non-root users to read from it at least?
On my setup
ls -l /dev/dvd
lrwxrwxrwx root root yada yada /dev/dvd->/dev/hdd
ls -l /dev/hdd
br--r--r-- root root yada yada /dev/hdd

Yes, the command I used for used for mplayer (mplayer -dvd 1) worked fine while logged in as root. I made it so I can mount dvd's as user as well.