I have a customer's DV7 laptop in for a liquid spill. He told be that everything works except that some of the keyboard keys stick or dont function. Based on what he told be I was thinking just a quick keyboard swap.
Before ordering the new keyboard I tested the laptop. Here is what is strange;
All keys function on the keyboard when at the password screen for the machine. Once the password is typed in and the desktop loads, NO keys work. The mouse works fine. I plugged an external USB keyboard in, it also does not work.
I tried these same steps with safemode and obtained the same result. So I need your opinions on this, obvious software/driver issue? Motherboard issue affecting only the keyboard once the operating system loads....?
I would remove the keyboard completely, and try the USB keyboard (unplug all other external devices). After that, I would check Sticky Keys in Accessibility Options. I guess my line of reasoning is that some key combo is active (and sticky) in the Windows desktop environment that is not active in the Welcome Screen.
It would also be interesting to know what happens if you boot via a Linux Live CD...
Are you hearing any beeps or seeing any errors at startup?
I think perhaps the post test detects the keyboard (as ok) but then when it uses the OS (after boot) to use the keyboard it finds difficulty. I spilt red wine over a portable keyboard some time ago and had similiar symptoms and it was due to keys being stuck (not the keys but the membrane below!!) hope this helps.