Copy function $template_cat_list from themes/sample/theme.php (first check if you alredy have it in your theme.php ) and:
1) Delete this code to delete Albums Files text:
<td class="tableh1" width="10%" align="center">{ALBUMS}</td>
<td class="tableh1" width="10%" align="center">{PICTURES}</td>
and change 80% to 100% in this line of code:
<td class="tableh1" width="80%" align="left">{CATEGORY}</td>
2) Delete this code to delete the numbers:
<td class="catrow" align="center">{ALB_COUNT}</td>
<td class="catrow" align="center">{PIC_COUNT}</td>
This is function $template_cat_list with the above code deleted.
/******************************************************************************
** Section <<<$template_cat_list>>> - START
******************************************************************************/
// HTML template for the category list
$template_cat_list = <<<EOT
<!-- BEGIN header -->
<tr>
<td class="tableh1" width="100%" align="left">{CATEGORY}</td>
</tr>
<!-- END header -->
<!-- BEGIN catrow_noalb -->
<tr>
<td class="catrow_noalb" colspan="3"><table border="0"><tr><td align="left">{CAT_THUMB}</td><td align="left"><span class="catlink">{CAT_TITLE}</span>{CAT_DESC}</td></tr></table></td>
</tr>
<!-- END catrow_noalb -->
<!-- BEGIN catrow -->
<tr>
<td class="catrow" align="left"><table border="0"><tr><td>{CAT_THUMB}</td><td><span class="catlink">{CAT_TITLE}</span>{CAT_DESC}</td></tr></table></td>
</tr>
<tr>
<td class="tableb tableb_alternate" colspan="3">{CAT_ALBUMS}</td>
</tr>
<!-- END catrow -->
<!-- BEGIN footer -->
<tr>
<td colspan="3" class="tableh1" align="center"><span class="statlink">{STATISTICS}</span></td>
</tr>
<!-- END footer -->
<!-- BEGIN spacer -->
<img src="images/spacer.gif" width="1" height="7" border="" alt="" /><br />
<!-- END spacer -->
EOT;
/******************************************************************************
** Section <<<$template_cat_list>>> - END
******************************************************************************/
You can delete all the tr if you don't want Category text either:
<tr>
<td class="tableh1" width="80%" align="left">{CATEGORY}</td>
<td class="tableh1" width="10%" align="center">{ALBUMS}</td>
<td class="tableh1" width="10%" align="center">{PICTURES}</td>
</tr>