Why doesn't my HP Pavilion ze2000 start up in any mode?

I think you need to start your computer with your operating system disk and instead of install try selecting repair disk. If that does not work you can try an archive and install to save your data. The final option is to format the drive and reinstall the OS. In any case when you get the computer working I would make sure I had very good malware and anti-virus programs installed and functioning. A check of the forums suggest a possibility of a heat problem so you could try a inexpensive cooler stand and see if it helps. Good luck.