I just bought this laptop. When I turn ON the power button, I get a small blue screen which says "Power ON Password and a picture of a Key (just like key of a lock). How do I proceed further. Thanks.

Support Information:
Device Type: BIOS / Motherboard
Manufacturer: Compaq
Model: EVO N600C
Interface: Other
Operating System: Windows 2000 Workstation
Age of Device: < 2 years old
FCCID:

Find it on DriverGuide (http://members.driverguide.com/index.php?action=srch&sm=b&aax=&qa6=236&qa5=1&qa7=1700&dp=2&qm0=EVO+N600C&jmd=and&fzz=d) | Find it with Google (http://www.google.com/search?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=Compaq+BIOS+%2F+Motherboard++EVO+N600C+Windows+2 000+Workstation+) | Research manufacturer Compaq (http://members.driverguide.com/index.php?action=getinfo&companyid=236)

It sounds like your laptop has been password protected. Other than knowing what the password is and typing it, I would suggest you contact HP tech support.

http://h20000.www2.hp.com/bizsupport/TechSupport/Home.jsp?&lang=en&cc=us&prodTypeId=321957&prodSeriesId=316673&lang=en&cc=us

Why I am unable to type anything using the keyboard, Only enter/return key works when I see the Blue screen which says power ON password followed by a picture of a key.

The only keys that will work are the one's representing the password and nothing will happen until the correct password is typed.

Maybe keyboard is faulty. Most of the Compaq / HP models have a reset procedure which would clear the BIOS power on password for this you may have to disassemble the laptop and perform certain reset actions.

Get in touch with HP technical support and request for a Service Manual with this reset procedure.