Ya this fix will still work for you. I had MCE 2002 too, one of the steps above is a registry change which "upgrades" you from 2002 to 2005. So just follow all the steps and it should work fine. It did for me :) 

(only then I went and screwed up my media codecs, but that was something different I did and is all fixed now too)

I'm not really getting any error messages, but I think my problem may be related to SP3.  After recently installing a Visiontek 550 in my son's MCE 05 PC, I tried it out.  Live TV worked; I thought everything was fine.  I tried hitting the record button.  Red record icon comes up, then disappears.  When I set it to record a show using the guide, when the time came it says something about the show could not be recorded and to restart the computer.  Restarting doesn't help.  If you hit record while displaying Live TV, you can go to Recorded TV and it will show the name of the program currently being displayed on Live TV and supposedly being recorded, but if you select it and choose Watch it will say something about missing a critical component.  I've tried tons of stuff...system restore, re-registering folowing the instructions I've seen around here, uninstalling and reinstalling .net 1.1 along with the SP1 update, and none of that's worked.  What else can I try?

This is the third time I've had to follow this process after doing a clean install of Windows + MCE + SP2&SP3. Many thanks for taking the time to set out these steps for getting MCE up and running.

Thank you! It's finally working like it used to! I LOVE YOU!!!! xD THANK YOU SOOOO MUCH! I've been trying to fix it for the past few weeks, and this took me like ten minutes. Thanks!

OMG Thank you so much, Coolhp. I have spent days trying all the fixes on this site & others. This is the only method that worked for me. I just wanted to register to personally thank Coolhp & all the contributers on this site. Do the steps exactly as laid out & it may just fix your MCE errors on a SP3 XP machine. I only wish I would have found this earlier. It never showed in any google searches for media center errors. I found it only after searching fo ways to uninstall SP3. I had no eshell errors, but did have the "tuner not found" & "critical process failure" (code 2 & 3). Everything is working sweet now without having to run mcerepair or any of the other fixes. I am also running .NET Framework 4 with no problems. When it worked I danced around my room & yelled "I Love You Coolhp!"& "you are a freaking genius! LOL. I know this post is slightly old, but should be resurrected for more to find.