Hi guys, i've started to write some website and bumped into this problem.. have tried all the solutions on the forum that i could search for..
E.g clear any blanks on the main_left.php (code shown below)
no echo on main_left.php
and also ob_start();
none of it works...

Warning: Cannot modify header information - headers already sent by (output started at C:\xampp\htdocs\cags\menu\main_left.php:82) in C:\xampp\htdocs\cags\phpBB3\common.php on line 58

Code for main_left.php

<!-- Left-side panel of main page -->
		<div id="categories">
		  <div id="categories_header">
			<h2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;User Refine</h2>
		  </div>
		  <div>
           	<p>Budget</p>
            <div align="left">
				<select>
                	<option>--Please Select--</option>
                	<option>Below RM1000</option>
  					<option>RM1000 - RM1999</option>
  					<option>RM2000 - RM2999</option>
  					<option>RM3000 - RM3999</option>
                    <option>RM4000 - RM4999</option>
                    <option>RM5000 - RM5999</option>
                    <option>RM6000 - RM6999</option>
                    <option>RM7000 - RM7999</option>
                </select>
            </div>
           	<p>Processor</p>
            <div align="left">
				<select>
                  <option>--Please Select--</option>
				  <option>Intel Atom</option>
				  <option>2nd Gen Intel Core vPro</option>
				  <option>2nd Gen Intel Core i3</option>
				  <option>2nd Gen Intel Core i5</option>
				  <option>2nd Gen Intel Core i7</option>
				  <option>2nd Gen Intel Core i7 Extreme</option>
				  <option>AMD Athlon</option>
				  <option>AMD Athlon X2 Dual-Core</option>
				  <option>AMD Athlon II</option>
				  <option>AMD Phenom</option>
				  <option>ADM Phenom II</option>
                </select>
            </div>
            <p>Graphic Card</p>
            <div align="left">
				<select>
                  <option>--Please Select--</option>
				  <option>ATI Radeon HD 4000 Series</option>
				  <option>ATI Radeon HD 5000 Series</option>
				  <option>ATI Radeon HD 6000 Series</option>
				  <option>NVDIA GeForce Series</option>
				  <option>NVDIA GeForce GT Series</option>
				  <option>NVDIA GeForce GTS Series</option>
				  <option>NVDIA GeForce GTX Series</option>
                </select>
           	</div>
            <p>Hard Drive</p>
            <div align="left">
				<select>
                  <option>--Please Select--</option>
				  <option>250GB</option>
				  <option>320GB</option>
				  <option>500GB</option>
				  <option>1TB</option>
				  <option>2TB</option>
				  <option>4TB</option>
                </select>
           	</div>
            <p>Memory (RAM)</p>
            <div align="left">
            	<select>
                  <option>--Please Select--</option>
            	  <option>1GB DDR3</option>
            	  <option>2GB DDR3</option>
            	  <option>4GB DDR3</option>
            	  <option>6GB DDR3</option>
            	  <option>8GB DDR3</option>
                  <option>16GB DDR3</option>
                </select>
            </div>
            <p></p>
            <div algin="left">
				<button type="button">Search</button>
            </div>
            <div class="clearthis">&nbsp;</div>
          </div>
		  <div class="clearthis">&nbsp;</div>
	  </div>