BleepingComputer.com: Black screen when trying to install new PCI card

Well I tried to install new GeForce 8400 GS to my old HP Pavilion a1010n.Intel®82845G/GL/GE/PE/GV Graphics Controller..It is part of motherboard so couldn't remove..OK first turn off pc.remove all cables power down..open case install card..hook cables back up power up..run install cd hook vga cable to new card no screen..read help tells me to go in Bios change card settings..but no I have to try some things on my own...soooo.I go to my display setting and now See my new card w/old one and it tells me I have 2 monitors so a few clicks later I think I have solved my problem but i made my desk top monitor num.2 any way new card would not play lg flat screen tv.and after reboot no screen..oh crap what did I do..so I have my third cup of coffee and pull out new card yippy have screen back but now cant change setting back in display guess pc cant see card so no longer have options for 2 monitors..I don't have spare monitor or cable for that matter I am on vga port now there is a serial port but can't hook that to tv if any of this makes any sense please help

Thank you Dutchvic

Edit: Moved topic from XP to the more appropriate forum. ~ Animal

Does this your HP Pavilion a1010n?
http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00303941&cc=us&lc=en&dlc=en&product=459879
or
http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00068983&tmp_task=prodinfoCategory&cc=us&dlc=en&lc=en&product=459879#N25

From that 2 link, your Mainboard doesn't have VGA Slot on it and that means you couldn't upgrade VGA on it.