HP laserjet 1500l error lights

Hi,

I have the following problem. After I changed the Image Drum, the printer worked fine for about 2 weeks. Now when I turn my printer on, on the printer control (where you can see if printer is ready or not) lights keep on cycling from one to another.

I have
- Installed newest USB2 Drivers
- Reinstalled the HP Orignial Drivers
- Looked trough all the the "normal" error Messages on
- Tried 2 other PC's, new cables (always the same).

The PC correctly notices the printer. Also I have no control over the Printer, even from the control panel.

I have no further ideas, can someone help me please?