I think this started with Kubuntu 10.10 or 00.04, both of which I used only while waiting for an 11.10 CD (downloading an OS doesn't always work well with lowest speed DSL). At first it seemed only my 500 Gb SATA was affected. Then I installed on another HD. At first it was fine, but when I had to abort a print job to change the cartridge the trouble started again. The MB, RAM and CPU are only a couple of months old. I am running from a CD now, SeaTools shows the SATA as having failed a read-write test at 80% completion, but the 250 Gb passed yet won't because of out of range. I've been using the same 22" LCD monitor for a couple of years.
Solution: Tried another monitor; no problem with that one.

Hi,

Please respond with your solution instead of editing OP and providing answers. That way anyone searching will hopefully find a through solution.

BTW, you can mark the thread as [Solved] via thread tools or clicking on 'Please Mark this thread as solved if you feel a solution has been provided.' at the top of the window.