<p>I need to add a row to a spreadsheet using VBScript on a PC that does not have Microsoft Office installed.</p>

<p>I tried [<code>Set objExcel = CreateObject("Excel.Application")</code>]</p>

<p>Since Excel does not exist on the PC I cannot create this object.</p>

<p>Is there a way to modify a spreadsheet without Excel?</p>

Without Excel installed I cannot see how you will be able to change an Excel document.
However, If your are using Excel 2007 spreadsheets (xslx) then you should able to use the OpenXML functionality of the .NET Framework to update the contents without Excel physically being installed.
Take a look
here
for more information on Office OpenXML.