The drivers for the HP Scanjet 3500 and others have been listed below. The driver was released in 2003 and was made to work on Windows XP and Windows 2000. Check your hardware for the file before you download it. This works for the 3530 and also the Scanjet 3570c as listed.
The driver for this USB scanner is listed here.
Note: There is no Windows 7 driver for this hardware. This was the last driver for this hardware as it is very old and was never updated again. What you could try is running the driver in compatibility mode.
1. Place the driver installation file on the Desktop.
2. Right Click the driver installation file and select Properties/Compatibility Tab.
3. Select Windows XP for compatibility mode.
4. Click Apply
5. Right Click the file and select the Run As Administrator option to install.