You could try the windows vista driver and if it won't install and you get an error do the following :
To install a driver/program in compatibility mode - right click the setup.exe file - click properties - click compatibility - check run in compatibility with vista etc - check run as administrator - leave the rest blank. Start setup.exe and install.
Link to hp site with vista driver - Software & Driver Downloads HP Pavilion dv9819wm Entertainment Notebook PC - HP Customer Care (United States - English)
If your hp uses the realtek audio chip you can go here and download the latest Windows 7 driver - download from Guru3D.com
If none of this works you could find a similar laptop on the hp site and if it uses the conexant audio and supports Windows 7- download it and try it. Or just bing or google for a Windows 7 32 bit audio driver for your dv9819wm laptop.