disk read error / Asus A7V 133 Mother Board

[wbracey]

My A7V 133 with 1.4 GHz Thunderbird and 512 MB RAM was running fine, but I needed more memory for the large finite element models being run on this machine. So I added a second 512 MB DIMM, and at the next bootup I got the message "A disk read error has occurred. Insert a system diskette and restart the system." I removed the new DIMM and rebooted; same message. I moved the HDD from the Promise ATA 100 connector to the IDE connector, and I noticed one difference: there was a short grinding noise from the HDD on the ATA 100 that did not occur on the IDE. Otherwise, same message.

Finally, I booted from an NT4.0 CD, formatted the HDD, and began to reinstall NT. It did not appear to have any problem accessing the HDD, which was on the IDE connector. But at the point in the NT installation where it asks you to remove all CD's and floppies and reboot from the hard drive...whammo! same message.

I've checked all the jumpers; the board is set in jumper free mode. I'm sure the DIMM I used was compatible. I have several identical machines that run fine with 1024 MB RAM.

Any other ideas out there?