Sevastian,
Given a data setup like this:
<TABLE style="WIDTH: 180pt; BORDER-COLLAPSE: collapse" border=0 cellSpacing=0 cellPadding=0 width=239><COLGROUP><COL style="WIDTH: 48pt" width=64><COL style="WIDTH: 50pt; mso-width-source: userset; mso-width-alt: 2413" width=66><COL style="WIDTH: 82pt; mso-width-source: userset; mso-width-alt: 3986" width=109><TBODY><TR style="HEIGHT: 15pt" height=20><TD style="BORDER-BOTTOM: #d4d0c8; BORDER-LEFT: #d4d0c8; BACKGROUND-COLOR: transparent; WIDTH: 48pt; HEIGHT: 15pt; BORDER-TOP: #d4d0c8; BORDER-RIGHT: #d4d0c8" height=20 width=64></TD><TD style="BORDER-BOTTOM: #d4d0c8; BORDER-LEFT: #d4d0c8; BACKGROUND-COLOR: transparent; WIDTH: 50pt; BORDER-TOP: #d4d0c8; BORDER-RIGHT: #d4d0c8" width=66>
A
</TD><TD style="BORDER-BOTTOM: #d4d0c8; BORDER-LEFT: #d4d0c8; BACKGROUND-COLOR: transparent; WIDTH: 82pt; BORDER-TOP: #d4d0c8; BORDER-RIGHT: #d4d0c8" width=109>
B
</TD></TR><TR style="HEIGHT: 15.75pt" height=21><TD style="BORDER-BOTTOM: #d4d0c8; BORDER-LEFT: #d4d0c8; BACKGROUND-COLOR: transparent; HEIGHT: 15.75pt; BORDER-TOP: #d4d0c8; BORDER-RIGHT: #d4d0c8" height=21 align=right>
1
</TD><TD style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: windowtext 0.5pt solid; BACKGROUND-COLOR: transparent; BORDER-TOP: windowtext 0.5pt solid; BORDER-RIGHT: windowtext 0.5pt solid" class=xl63>
HeaderA
</TD><TD style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: windowtext; BACKGROUND-COLOR: transparent; BORDER-TOP: windowtext 0.5pt solid; BORDER-RIGHT: windowtext 0.5pt solid" class=xl63>
Non-numbers?
</TD></TR><TR style="HEIGHT: 15pt" height=20><TD style="BORDER-BOTTOM: #d4d0c8; BORDER-LEFT: #d4d0c8; BACKGROUND-COLOR: transparent; HEIGHT: 15pt; BORDER-TOP: #d4d0c8; BORDER-RIGHT: #d4d0c8" height=20 align=right>
2
</TD><TD style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: windowtext 0.5pt solid; BACKGROUND-COLOR: transparent; BORDER-TOP: windowtext; BORDER-RIGHT: windowtext 0.5pt solid" class=xl64>
1
</TD><TD style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: windowtext; BACKGROUND-COLOR: transparent; BORDER-TOP: windowtext; BORDER-RIGHT: windowtext 0.5pt solid" class=xl64>
No
</TD></TR><TR style="HEIGHT: 15pt" height=20><TD style="BORDER-BOTTOM: #d4d0c8; BORDER-LEFT: #d4d0c8; BACKGROUND-COLOR: transparent; HEIGHT: 15pt; BORDER-TOP: #d4d0c8; BORDER-RIGHT: #d4d0c8" height=20 align=right>
3
</TD><TD style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: windowtext 0.5pt solid; BACKGROUND-COLOR: transparent; BORDER-TOP: windowtext; BORDER-RIGHT: windowtext 0.5pt solid" class=xl64>
1a
</TD><TD style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: windowtext; BACKGROUND-COLOR: transparent; BORDER-TOP: windowtext; BORDER-RIGHT: windowtext 0.5pt solid" class=xl64>
Yes
</TD></TR><TR style="HEIGHT: 15pt" height=20><TD style="BORDER-BOTTOM: #d4d0c8; BORDER-LEFT: #d4d0c8; BACKGROUND-COLOR: transparent; HEIGHT: 15pt; BORDER-TOP: #d4d0c8; BORDER-RIGHT: #d4d0c8" height=20 align=right>
4
</TD><TD style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: windowtext 0.5pt solid; BACKGROUND-COLOR: transparent; BORDER-TOP: windowtext; BORDER-RIGHT: windowtext 0.5pt solid" class=xl64>
</TD><TD style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: windowtext; BACKGROUND-COLOR: transparent; BORDER-TOP: windowtext; BORDER-RIGHT: windowtext 0.5pt solid" class=xl64>
No
</TD></TR><TR style="HEIGHT: 15pt" height=20><TD style="BORDER-BOTTOM: #d4d0c8; BORDER-LEFT: #d4d0c8; BACKGROUND-COLOR: transparent; HEIGHT: 15pt; BORDER-TOP: #d4d0c8; BORDER-RIGHT: #d4d0c8" height=20 align=right>
5
</TD><TD style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: windowtext 0.5pt solid; BACKGROUND-COLOR: transparent; BORDER-TOP: windowtext; BORDER-RIGHT: windowtext 0.5pt solid" class=xl64>
2
</TD><TD style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: windowtext; BACKGROUND-COLOR: transparent; BORDER-TOP: windowtext; BORDER-RIGHT: windowtext 0.5pt solid" class=xl64>
No
</TD></TR><TR style="HEIGHT: 15pt" height=20><TD style="BORDER-BOTTOM: #d4d0c8; BORDER-LEFT: #d4d0c8; BACKGROUND-COLOR: transparent; HEIGHT: 15pt; BORDER-TOP: #d4d0c8; BORDER-RIGHT: #d4d0c8" height=20 align=right>
6
</TD><TD style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: windowtext 0.5pt solid; BACKGROUND-COLOR: transparent; BORDER-TOP: windowtext; BORDER-RIGHT: windowtext 0.5pt solid" class=xl64>
b2
</TD><TD style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: windowtext; BACKGROUND-COLOR: transparent; BORDER-TOP: windowtext; BORDER-RIGHT: windowtext 0.5pt solid" class=xl64>
Yes
</TD></TR></TBODY></TABLE>
In cell B2 and copied down is this formula:
=IF(OR(TRIM(A2)="",SUMPRODUCT(--(NOT(ISNUMBER(--MID(A2,ROW(INDIRECT("1:"&LEN(A2))),1)))))=0),"No","Yes")