Well if you got an error related to the hard drive then its better to check the hard drive whether is faulty or not..
1.Shut the system down.
2.Restart the system and tap on the F10 key for while till we dont get to the set up utility.
3.As soon as we get to the BIOS screen try locating an optionw which reads as DIAGNOSTICS, it would be the third option at the top,
4.Select that option using the arrow keys on the keyboard and hit enter.
5.It would show us an option which reads as Primary Hard drice self test..
6.Hit enter again to start the test.
7.There are 2 types of tests.
8.As soon as we start the test it would start the SHORT TEST first which would take a couple of minutes.
9.If it comes with any errors then call hp and ask them to replace the hard drive.
10.If the short test passes and the comprehensive test starts then let that test run completely which might take an hour as well..
11.If this test goes fine then the hard drive is fine and you are facing trouble because of the graphices card installed on the system.
12. I am providing you a couple of drivers which you can try installing depending on the operating system installed on the system.but you need to first check the hard drive and then perform these steps..
I believe the system was shipped with a 64 Bit Vista which NVIDIA graphics card.
I am providing you the drivers for that
ftp://ftp.hp.com/pub/softpaq/sp41501-42000/sp41696.exe
You can also try to update the BIOS which would the next step if the above steps does not help..
The link is :
ftp://ftp.hp.com/pub/softpaq/sp45001-45500/sp45138.exe
Hope this works
Regards
KEN