My website is horrible in IE but in Firefox it's fine?

/****************************************************************/
/* 1. BACKGROUND AND TEXT COLOURS */
/****************************************************************/

/* 1.1 Default background colour and text colour */

BODY {BACKGROUND-COLOR: #282828;}

.pun {COLOR: #C7C7C7}

DIV.box,  #adminconsole FIELDSET TH, .rowodd, .roweven {BACKGROUND-COLOR: #323232}
#adminconsole TD, #adminconsole TH {BORDER-COLOR: #323232}

/* 1. 2 Darker background colours */

TD.tc3, TD.tc4, TD.tcmod, #brdfooter DIV.box {BACKGROUND-COLOR: #2b2b2b}
#adminconsole FIELDSET TD, #viewprofile DD, DIV.forminfo, DIV.blockmenu DIV.box, #adstats DD {BACKGROUND-COLOR: #363636}

.pun BLOCKQUOTE, DIV.codebox {BACKGROUND-COLOR: #333333}

/* 1.3 Main headers and navigation bar background and text colour */

.pun H2, #brdmenu { BACKGROUND-COLOR: #111111; COLOR: #FFF; 
background-image:url(../../img/3rxnet/cell.gif) }

/* 1.4 Table header rows */

.pun TH {background-repeat: repeat-x;}

/* header logo */
.pun H1 
{
/* your logo and position */
background-image: url(../../img/3rxnet/logo_r.gif);
background-repeat: no-repeat;
background-position: center; /* you set your logo position here */
display: block;
height: 70px;/* logo height in here add width: size px if u need*/
}
 
/*header title*/
.pun H1 span
{
/* your font style */
color: #666666;
font-size: 0px; /* title size */
font-family: Tahoma, Verdana, Arial, Helvetica, sans-serif;
text-transform: none ; /* transform text: uppercase, capitalise */
text-decoration: underline; /* decoration: none, overline */
 
/* position for your text (board title) with the logo */
position: absolute; 
top: 0px; 
left: 0px; 
}

div#brdheader #brdtitle {
height: 118px; /* Replace with height of your header image */
padding: 0
}
#brdtitle span, #brdtitle p {
position: absolute;
display: block;
overflow: hidden;
width: 1em;
left: -999em
}
#brdtitle h1 {
width: 1090px; /* Replace with width of your header image */
height: 118px; /* Replace with height of your header image */
background: url('/img/logo_r.gif
}



/* 1.5 Fieldset legend text colour */

.pun LEGEND {COLOR: #FFFFFF}

/* 1.6 Highlighted text for various items */

.pun DIV.blockmenu LI.isactive A, #posterror LI STRONG {COLOR: #D4D4D4}

/****************************************************************/
/* 2. POST BACKGROUNDS AND TEXT */
/****************************************************************/

/* 2.1 This is the setup for posts. */

DIV.blockpost DIV.box, DIV.postright, DIV.postfootright, #postpreview {BACKGROUND-COLOR: #202020}
DIV.postright, DIV.postfootright {BORDER-LEFT-COLOR: #303030}
DIV.postleft, DIV.postfootleft, DIV.blockpost LABEL {BACKGROUND-COLOR: #303030}

/* 2.2 Background for post headers and text colour for post numbers in viewtopic */

DIV.blockpost H2 {BACKGROUND-COLOR: #000000; text-align: left}
DIV.blockpost H2 SPAN.conr {COLOR: #A19E96}

/* 2.3 This is the line above the signature in posts. Colour and background should be the same */

.pun HR {BACKGROUND-COLOR: #606060;    COLOR: #606060}

/* 2.3 This is the line above the signature in posts. Colour and background should be the same */

.pun HR {BACKGROUND-COLOR: #111111; COLOR: #111111}

/****************************************************************/
/* 3. BORDER COLOURS */
/****************************************************************/

/* 3.1 All external borders (H1 is the board title) */

DIV.box {BORDER-COLOR: #111111}

/* 3.2 Makes the top border of posts match the colour used for post headers */

DIV.blockpost DIV.box {BORDER-COLOR: #111111 #111111 #111111}

/* 3.3 Table internal borders. By default TH is same as background so border is invisible */

.pun TD {BORDER-COLOR: #111111}
.pun TH {BORDER-COLOR: #111111}

/* 3.4 Creates the inset border for quote boxes, code boxes and form info boxes */

.pun BLOCKQUOTE, DIV.codebox, DIV.forminfo, DIV.blockpost LABEL {BORDER-COLOR: #000000; background-color: #888888;color: #282828}

/* 3.5 Gecko's default fieldset borders are really nasty so this gives them a colour
without interferring with IE's rather nice default */

.pun DIV>FIELDSET {BORDER-COLOR: #111111}

/****************************************************************/
/* 4. LINK COLOURS */
/****************************************************************/

/* 4.1 This is the default for all links */

.pun A:link, .pun A:visited {COLOR: #AE3903; text-decoration: none}
.pun A:hover {COLOR: #AE4903; text-decoration: none}

/* 4.2 This is the colour for links in header rows and the navigation bar */

.pun H2 A:link, .pun H2 A:visited {COLOR: #D4D4D4; text-decoration: none}
.pun H2 A:hover {COLOR: #D4D4D4; text-decoration: none}

/* 4.3 This is for closed topics and "hot" links */

LI.postreport A:link, LI.postreport A:visited, TR.iclosed TD.tcl A:link, TR.iclosed TD.tcl A:visited {COLOR: #888}
LI.postreport A:hover, TR.iclosed TD.tcl A:hover {COLOR: #AAA; text-decoration: line-through}
LI.maintenancelink A:link, LI.maintenancelink A:visited {COLOR: #FF4000; text-decoration: blink}
LI.maintenancelink A:hover {COLOR: #FF5010; text-decoration: blink}

/****************************************************************/
/* 5. POST STATUS INDICATORS */
/****************************************************************/

/* These are the post status indicators which appear at the left of some tables. 
.inew = new posts, .iredirect = redirect forums, .iclosed = closed topics and
.isticky = sticky topics. The default is "icon". By default only .inew is different.*/

 
DIV.icon {background:url(../../img/3rxnet/icon.gif)}
DIV.inew {background:url(../../img/3rxnet/icon_new.gif)}
TR.isticky DIV.icon {background:url(../../img/3rxnet/sticky.gif)} 
TR.isticky DIV.inew {background:url(../../img/3rxnet/sticky_new.gif)}
TR.iclosed DIV.icon {background:url(../../img/3rxnet/closed.gif)}
 
TR.iredirect DIV.icon {background:url(../../img/3rxnet/redirect.gif)}

/* FACTICE BUTTON POST AND REPLY */
.pun p.postlink, #conr
{
/* align the text in button */
TEXT-ALIGN: CENTER;
 
/* aling the button on the border */
POSITION: RELATIVE; 
TOP : 0px;
LEFT: 6px;
 

 
/* color the button */
BACKGROUND-COLOR: #111111;
 
/* added an image background */
BACKGROUND-IMAGE: url(../../img/3rxnet/bg_button.gif);
 


/*header title*/
.pun H1 span
{
/* your font style */
display: none;
}