I can only recommend you try to use the manage attachments bar below every post box.
<FIELDSET class=fieldset><LEGEND>Miscellaneous Options</LEGEND><LABEL for=cb_signature><INPUT id=cb_signature tabIndex=1 type=checkbox CHECKED value=1 name=signature>Show your signature</LABEL>
<LABEL for=cb_parseurl><INPUT id=cb_parseurl tabIndex=1 type=checkbox CHECKED value=1 name=parseurl>Automatically parse links in text</LABEL>
<LABEL for=cb_disablesmilies><INPUT id=cb_disablesmilies tabIndex=1 type=checkbox value=1 name=disablesmilies>Disable smilies in text</LABEL>
</FIELDSET>
<FIELDSET class=fieldset><LEGEND>Attach Files</LEGEND>Valid file extensions: gif jpe jpeg jpg png txt xls
<SCRIPT src="clientscript/vbulletin_attachment.js?v=368" type=text/javascript></SCRIPT><SCRIPT type=text/javascript> <!-- var newpost_attachmentbit = '\r\n
\r\n
%5$s\r\n (%6$s)\r\n
'; vB_Attachments = new vB_Attachment('attachlist', ''); document.write('<input type="button" id="manage_attachments_button" class="button" tabindex="1" style="font-weight:normal" value="Manage Attachments" title="Click here to add or edit files attached to this message" onclick="vB_Attachments.open_window(\'newattachment.php?t=567383&poststarttime=1205078683&posthash=9f792fc4316a0831f648e659fa395b29\', 480, 480, \'5175710\')" />'); //--> </SCRIPT><INPUT class=button id=manage_attachments_button title="Click here to add or edit files attached to this message" style="FONT-WEIGHT: normal" onclick="vB_Attachments.open_window('newattachment.php?t=567383&poststarttime=1205078683&posthash=9f792fc4316a0831f648e659fa395b29', 480, 480, '5175710')" tabIndex=1 type=button value="Manage Attachments"> <NOSCRIPT></NOSCRIPT>
</FIELDSET>
Insert c:\desktop\....
Upload File from your Computer