Comment 6 for bug 573557

I have the same problem. Just added an old hdd and did a clean install.

Hardware:
Asus P5NE-SLi Motherboard
Intel Q6600 Core2 Quad Processor
4GB DDR Ram
2x nvidia 8600 GT Video cards (linked by SLi cable)

Process was as follows:
1. Installed clean Ubuntu without problems
2. Logged in for first time without a problem
3. Installed the NVidia-Current drivers as provided by the Hardware Drivers panel in System --> Administration
4. Reboot and get a blank screen.

At this point I restarted into my regular build and took a look at the log files. Kern.log and messages in /var/log show the following lines:
May 2 13:22:01 eddy-testdesktop kernel: [ 266.445331] nvidia: module license 'NVIDIA' taints kernel.
May 2 13:22:01 eddy-testdesktop kernel: [ 266.445335] Disabling lock debugging due to kernel taint
May 2 13:22:01 eddy-testdesktop kernel: [ 267.034199] NVRM: The NVIDIA probe routine was not called for 2 device(s).
May 2 13:22:01 eddy-testdesktop kernel: [ 267.034203] NVRM: This can occur when a driver such as rivafb, nvidiafb or
May 2 13:22:01 eddy-testdesktop kernel: [ 267.034204] NVRM: rivatv was loaded and obtained ownership of the NVIDIA
May 2 13:22:01 eddy-testdesktop kernel: [ 267.034205] NVRM: device(s).
May 2 13:22:01 eddy-testdesktop kernel: [ 267.034207] NVRM: Try unloading the rivafb, nvidiafb or rivatv kernel module
May 2 13:22:01 eddy-testdesktop kernel: [ 267.034208] NVRM: (and/or reconfigure your kernel without rivafb/nvidiafb
May 2 13:22:01 eddy-testdesktop kernel: [ 267.034209] NVRM: support), then try loading the NVIDIA kernel module again.
May 2 13:22:01 eddy-testdesktop kernel: [ 267.034211] NVRM: No NVIDIA graphics adapter probed!
May 2 13:22:21 eddy-testdesktop kernel: Kernel logging (proc) stopped.