Yeah, but I changed a few things.

1) Font sizes and colors were removed from the BODY.
2) Fonts in the stylesheet were changed from px and pt to small, x-small and medium.
3) Added .menu and set up the menu row with it to change its color and font size easier.
4) All the sblocks stuff is for YaPP, you can remove those columns and adjust the widths.
5) Added .windowbg3 for my YaPP Blocks, .editor is also for YaPP.
6) Alphabetized all the styles, first by standard CSS types then by YaBB types.
7) Added BACKGROUND-COLOR=Transparent and other attribs where needed to comply with CSS standards, and removed attribs from styles (mostly font-family) where they were not needed.
7) Removed the nested tables on the top set (logo, menu, etc) and on the copyright set on the bottom.
8 Heavily commented for use with FrontPage so the columns and rows would show up.

I think that's about it, and with that said, here it is:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD><TITLE><yabb title></TITLE>
<META http-equiv=Content-Type content="text/html; charset=windows-1252">
<META name="description" content="<yabb title>" >
<META name="keywords" content="YaPP, YaBB SE, php, color scheme, template, css" >
<STYLE type="text/css">
<!--
A:link {COLOR: #005177; FONT-WEIGHT: bold;BACKGROUND-COLOR: transparent; TEXT-DECORATION: none;}
A:visited {COLOR: #005177; FONT-WEIGHT: bold; BACKGROUND-COLOR: transparent; TEXT-DECORATION: none;}
A:hover {COLOR: #CC3333; FONT-WEIGHT: bold; BACKGROUND-COLOR: transparent; TEXT-DECORATION: underline;}
BODY {COLOR: #000000; FONT-SIZE: small; FONT-FAMILY: Verdana, arial, helvetica, serif; BACKGROUND-COLOR: #FFFFFF;}
INPUT {COLOR: #000000; FONT-SIZE: x-small; BACKGROUND-COLOR: #AFC6DB;}
SELECT {COLOR: #000000; FONT-SIZE: x-small; BACKGROUND-COLOR: #AFC6DB;}
TD {COLOR: #000000; BACKGROUND-COLOR: transparent; }
TEXTAREA {COLOR: #000000; FONT-SIZE: x-small; BACKGROUND-COLOR: #AFC6DB;}
.bordercolor {BACKGROUND-COLOR: #6394BD;}
.catbg {FONT-SIZE: small; COLOR: #000000; FONT-WEIGHT: bold; BACKGROUND-IMAGE: url(YaBBImages/catbg.gif); BACKGROUND-COLOR: transparent;}
.code {FONT-SIZE: small; COLOR: #000000; BACKGROUND-COLOR: #CCCCCC; }
.editor {width : 100%; }
.help {CURSOR: help; BACKGROUND-COLOR: transparent; }
.hr {COLOR: #000000; BACKGROUND-COLOR: transparent; }
.meaction {COLOR: red; BACKGROUND-COLOR: transparent; }
.menu {FONT-SIZE: x-small; BACKGROUND-IMAGE: url(YaBBImages/catbg.gif); BACKGROUND-COLOR: transparent;}
.nav {COLOR: #000000; FONT-WEIGHT: bold; BACKGROUND-COLOR: transparent; TEXT-DECORATION: none; }
.nav:link {COLOR: #000000; FONT-WEIGHT: bold; BACKGROUND-COLOR: transparent; TEXT-DECORATION: none; }
.nav:visited {COLOR: #005177; FONT-WEIGHT: bold; BACKGROUND-COLOR: transparent; TEXT-DECORATION: none; }
.nav:hover {COLOR: #CC3333; FONT-WEIGHT: bold; BACKGROUND-COLOR: transparent; TEXT-DECORATION: underline; }
.quote {COLOR: #000033; FONT-SIZE: small; BACKGROUND-COLOR: #DEE7EF; }
.text1 {COLOR: #FFFFFF; FONT-SIZE: small; FONT-WEIGHT: bold; BACKGROUND-COLOR: transparent; }
.titlebg {COLOR: #FFFFFF; FONT-SIZE: small; BACKGROUND-COLOR: #6394BD;}
.windowbg {COLOR: #000000; FONT-SIZE: small; BACKGROUND-COLOR: #AFC6DB;}
.windowbg2 {COLOR: #000000; FONT-SIZE: small; BACKGROUND-COLOR: #F8F8F8;}
.windowbg3 {COLOR: #000000; FONT-SIZE: small; BACKGROUND-COLOR: #6394BD;}
// -->
</STYLE>
</HEAD>
<BODY>
<TABLE cellSpacing=0 cellPadding=0 width="99%" align=center border=0>
<TR>
<TD valign=middle align=center><!--webbot bot="PurpleText" PREVIEW="<yabb logo>" --><yabb logo></td>
</tr>
<tr>
<TD vAlign=middle align=right><!--webbot bot="PurpleText" PREVIEW="<yabb uname> <yabb im>" -->
<yabb uname><yabb im><BR><!--webbot bot="PurpleText" PREVIEW="<yabb mute>" -->
<yabb mute></TD>
</TR>
<TR vAlign=middle align=center >
<TD class=menu><!--webbot bot="PurpleText" PREVIEW="<yabb menu>" -->
<yabb menu></TD>
</TR>
<tr>
<td align=left height="22" ><!--webbot bot="PurpleText" PREVIEW="<yabb news>" --><br><yabb news></td>
</tr>
</TABLE>
<BR>
<TABLE cellSpacing=0 cellPadding=0 width="99%" align=center border=0>
<TR>
<TD>
<TABLE cellSpacing=1 cellPadding=0 width="100%" align=center border=0>
<TR>
<TD>
<TABLE cellSpacing=0 cellPadding=3 width="100%" align=center border=0>
<TR>
<TD vAlign=top width="15%">
<yabb sblocksl><!--webbot bot="PurpleText" PREVIEW="LEFT Blocks" -->
</TD>
<TD vAlign=top width="70%">
<yabb sblocksc><!--webbot bot="PurpleText" PREVIEW="CENTER Blocks" -->
<br>
<yabb main><!--webbot bot="PurpleText" PREVIEW="OR FORUM Tables" -->
<br>
<yabb sblocksbc><!--webbot bot="PurpleText" PREVIEW="and BOTTOM Center Blocks" -->
</TD>
<td vAlign=top width="15%">
<yabb sblocksr><!--webbot bot="PurpleText" PREVIEW="RIGHT Blocks" -->
</td>
</TR>
</TABLE>
</TD>
</TR>
</TABLE>
</TD>
</TR>
</TABLE>
<TABLE cellSpacing=0 cellPadding=0 width="90%" align=center border=0>
<TR>
<TD noWrap align=right><yabb VBStyleLogin><!--webbot bot="PurpleText" PREVIEW="VBStyleLogin " --></TD>
</TR>
</TABLE>
<BR>
<TABLE cellSpacing=0 cellPadding=0 width="90%" align=center border=0>
<TR>
<TD vAlign=middle align=right width="25%" >
<A href="http://www.mysql.com/"><IMG height=31 alt="Powered by MySQL" src="YaBBImages/mysql.gif" width=88 border=0></A>
<A href="http://www.php.net/"><IMG height=31 alt="Powered by PHP" src="YaBBImages/php.gif" width=88 border=0></A></TD>
<TD vAlign=middle align=center width="50%"><!--webbot bot="PurpleText" PREVIEW="Copyright Info" --><yabb copyright></TD>
<TD vAlign=middle align=left width="25%">
<A href="http://validator.w3.org/check/referer"><IMG height=31 alt="Valid HTML 4.01!" src="YaBBImages/vhtml.gif" width=88 border=0></A>
<A href="http://jigsaw.w3.org/css-validator/check/referer"><IMG height=31 alt="Valid CSS!" src="YaBBImages/vcss.gif" width=88 border=0></A>
</TD>
</TR>
</TABLE>
</BODY>
</HTML>
I'm not sure I have the new font size types set exactly the way you did originally, but I liked the look of them better. Feel free to modify them back... with this template, it's easier for us to change things. I think I also got the colors back to the original template, but may have missed one or two.
HTH, Mad Moya