Command Button If Statement to halt macro

[aka_krakur]

Okay, so I have a command button that formats the excel worksheet to look like this:

TEMPLATEShippedQuantity.xls
	A	B	C	D	E	F	G	H	I	J	K	L	M
1		Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
2	RX Acculink
3	1998	0	0	0	0	0	0	0	0	0	0	0	0
4	1999	0	0	0	0	0	0	0	0	0	0	0	0
5	2000	0	0	0	0	0	0	0	0	0	0	0	0
6	2001	0	0	0	0	0	0	0	0	0	0	0	0
7	2002	0	0	0	0	0	0	78	189	358	298	311	212
8	2003	317	326	327	356	320	433	387	287	350	518	473	564
9	2004	543	583	650	518	554	653	483	1082	2736	2323	2513	2229
10	2005	2463	2184	2363	2470	2778	3201	2582	2446	2839	2129	2302	2374
11	2006	2156	1827	2645	2258	2201	2411	1966	2561	97	0	0	0
ShippedQty-SummarybyYr

I want to add something to the commandbutton macro that says if Cell A1 is blank then pop up a message box that says "Copy/Paste New Data from Viper Drill-Down" and then end Macro without continuing.

Because if they click the button and it executes, right now it'll mess up at this stage because it's expecting data in a whole different format.

Looks more like this when it's okay to click the Command Button:

[HTML removed by admin]

 

[aka_krakur]

Also need some kind of statement that says if while commandbutton1 is hidden if data is pasted into worksheet, to unhide commandbutton.