Hi Trova,
The Asus A7S-LE indeed shows specifications of having an AGP slot. So you do have the 8500DV in the correct slot. This is a Sony VAIO PC, correct?
Unfortunately, you have to do some fancy footwork in order to get your system to recognize and use an AGP board... and some special steps needed for this DV version of the card.
Here's the steps:
1) Ensure you have the latest BIOS from SONY for your PC flashed. You should hit the sony website/support area and see if there are new BIOS's available for your exact model of PC.
2) With the latest BIOS installed, you'll need to disable the on-board SiS video in the BIOS or with a jumper. According to your last post, you're familiar with how to properly disable the on-board video. Do this again, then power off the computer for the new videocard installation.
3) After inserting the 8500DV into the AGP slot, it has a small molex connector near the back/bottom of the board. You will need to plug a hard-disk power cable into that molex connector before powering up the board. If you do not have a spare 4-prong power connector, you can buy a power-splitter to split another one.
---
At this step, you should be able to get the PC to at least boot up/POST test with the board installed. The "No Signal" problem should no longer occur... provided you have your monitor plugged into the new videocard and not the old on-board hehe.
You now have a few steps to do in order to get Windows to use/recognize the board.
1) Hit:
http://www.sis.com/download/
On this page, in the boxes mid-screen, select:
"Chipset Drivers"
then
"AGP (GART) driver"
then on the last box, select your operating system (I'm assuming "Windows XP"... not XP 64!).
Download and install these drivers.
Then hit
www.ati.com, use the Customer Care/Find a Driver link at the top of their page and grab the 5.9 Catalyst drivers with Control Panel. Install these and you should be in business.