Core modification for user.php ? HOW do I even begin to search for, or request???

I'm looking for some assistance in modifying a user profile page...

SKIP to bottom of post to bypass my frustration rant (not intended as a rant)

HOWEVER, using the search function here to look for any previous attempts that may have been posted, is nearly useless! First you must know what catagory to search in, because "search all" is not an option. Second, I have no idea where to look! (or why I SHOULD know where to look)
I want to know how to add a function to a user's profile. I've tried on numerous occassions and have gotten absolutely no where. Everytime I come back here looking for something, I get so frustrated with not knowing where to look, or HOW to look for what I need, I inevitably LEAVE.
The new site layout (to me) seems quiet a mess. So much so, I don't even know where to post what I'm looking for.
This is NOT intended as a rant, but more of a frustration with this site's functionality.(as far as FINDING something)

What I want: I want to ADD a script into the user page that displays something SPECIFIC to the user the page is FOR. (not for the user viewing it) Every attempt I have meda fails in a script error. HOWEVER I HAVE successfully made this work in MY profile page sig area, so that it shows a script relevent to the user VIEWING it. I've been trying to get this accomplished for over TWO YEARS! I'm not a "coder" or techno geek so 'geek speak' doesn't help either.
It took me over 15 minutes to get logged in, because the reset password function has a failure in it (never emailed me the reset), so I kept guessing until I finally got logged in. (also kept getting re-directed to a form page with every failure.)
While waisting over an hour TRYING to search for related information, AT BEST, I found LOTS of relivant QUESTIONS, yet NONE of them answered! (annoying)

I'm so frustrated with the level of difficulty in finding desired information, that I've decided to start a new thread to REQUEST help, but can't even figure out WHERE to do that!
Sorry for the word wall, so PLEASE could someone help me FIND where to look for what I want, or WHERE to ASK for it??? (Please DO NOT tell me to search the forums for what I want, as I have already spent an HOUR doing so!)

Topic: Modify userpage.php to include a script (embeded script?) that IS NOT modifiable by the user.

What do you mean by "that IS NOT modifiable by the user."?

Various plugins (Rating System, Ranking System, Signature) insert their objects into the user.php.
I want to create a plug in that will do the same with a script. Every time I have tried in the past, I either get a syntax error, or a script error. I CAN put the script in the user's sig, but because my site is set to "Sanitize" user level html, and because they can change it, I want to create the script to show ONLY in the user's profile as a fixed script (hard coded into user,php, or plug in)
I've tried this so many times and just can't get it to work. I tried creating a plugin, and using a shortcode to inject it but get errors now matter what I tried. I keep giving up out of frustration, but the need for it, keeps bringing me back to it.
We're an XBOX community, and need each gamer's 'Gamercard' to show in their profile. The SQL database USERNAME, is populated with the user's gamertag ONLY (langauge file updated to that as well) The script
works in the sig field, but the user can alter that, AND it appears in the forum... I want to make this script show in their profile ONLY, and NOT be editable by anyone. I need this in EVERY profile. For the purposes of this script the username is irrelivent, the image (or iframe) should still be there regardless)Example using an "anonymous" as the username, (to be pulled from username column in database) this would be the script rendered into user.php:##SANITISED## src="http://gamercard.xbox.com/anonymous.card" scrolling="no" frameBorder="0" height="140" width="204">anonymous##SANITISED##>I would assume that {gamercard} would be used in user.php and would call gamercard.php as a plugin.

If you look at MY sig, in my profile on this site, you'll see why I can't use it as a sig (aside from members changing it)