The usual suggestion would be to go to the manufacturer's support site for drivers, which is what I just did, and I ended up here:http://h20000.www2.hp.com/bizsupport/TechSupport/DriverDownload.jsp?prodNameId=410114&lang=hu&cc=hu&taskId=135&prodTypeId=12454&prodSeriesId=410112
It doesn't seem to have drivers for Windows 7, but Vista drivers usually work under Windows 7, too bad, that I can't see any video drivers under the Vista category. On the contrary, when I go to the XP category it offers several different kinds of drivers, for ATI, Intel and NVidia cards too. So you should find out first, what kind of card you have (GPU-Z http://www.techpowerup.com/gpuz/).
If it's ATI or NVidia, I'd go for the cards' support site, and look for Windows 7 or Vista drivers there.