What is the complete product name or product number?
There should be two letters at the end of what you already posted as identification of your desktop PC. a151cl , a1511in or a151kr.
You will need to upgrade memory to at least 1 GB to meet the windows 7 system requirements. Otherwise Windows 7 is a go.
To find the drivers just do a google search with A8N-LA windows 7 drivers as the key words. Windows 7 drivers for your desktop PC's motherboard are not available here on the HP web support servers portal or your PC.