I bought a used Compaq Armada 7770 Notebook, and when I attempt to boot up it gives me an error message that says: "Invalid system disk, replace the disk and then press any key". If I put in a windows boot disk it goes to the A:/, but you can't use it to "fdisk", "format", or "setup" to install Windows as the letters "i, k, o, m, u,and letter p" instead put in "5, 2, *, 0, 4, and -". I have an adapter to hook the notebook hard drive to my desktop computer, and many times I have used it to install an operating system (and windows cab files for configuration changes) when the notebook doesn't have a CD-Rom. However, when I do this I again get the "Invalid system disk, replace the disk and then press any key" message, even though the operating system boots correctly in other notebook computers. I have also used a known good keyboard, and double checked jumper settings on the hard drive to no avail. TIA - Jim

Sounds like a hardware problem with the motherboard keyboard decoder.