My Hitachi SuperScan 600 CRT monitor (bought before 2001) screen just started vibrating visably a few days ago. My pc's an emachine T3062, bought 12/04.
The only happening around that time was a neighborhood electrical power outage -- maybe the day before (?).

When the emachine's first booting up, there's no vibrating during the logo "e" or the "Windows XP ......(loading)" window. Vibration starts at the "Windows is starting up" window and continues from then on.

The pc and monitor were plugged into an Isotel Ultra TrippLite surge protector (bought 2002 or earlier) during the power outage.

Another older CRT monitor also vibrates in the same way on the same pc.

But, ... the Hitachi monitor does not vibrate on a friend's computer.

Also, I couldn't get sound out of my Cambridge SoundWorks FPS2000 (old) Digital Multimedia Speaker System, altho a CD was playing. There was sound the day before the power outage.

A semi-techie friend sez I should restore Windows XP in the emachine.
I'm not sure.

What would you consider, and in what order?

I'm obviously not a techie (tho interested in tech. stuff), so please explain it as tho to your grandma.

Thank you!

When booting up the GA uses basic settings, however, when the OS takes hold IT'S using enhanced mode drivers. Try booting in Safe mode for a check.
The drivers may be corrupt and may need to be re-installed. This also may be symptoms of a bad connection at the monitor cable/GA port.

Thanks, mechbas, for your reply!
Which drivers do you refer to? I think I'd have to re-install drivers from a mfr's. website, as emachine supplies only a "Restore" CD.
Re: the monitor cable/GA port: what does "GA" mean? (Wikipedia didn't say.) I do know that the monitor cable has had an apparent break for many years, so to avoid having my screen go shocking pink, I kink over the monitor cable against itself: then the color's OK.
New development: I just changed, in Control Panel, the monitor's refresh rate from 75 Hz where it's been ever since I got it (about 11 years) down to 60 Hz, and, voila!, the screen vibration stopped. It did not stop tho at 72 or 70 Hz. And I'm not seeing flicker at 60 Hz, which was why I wanted a high refresh rate.
Now that it ain't broke, I don't wanna "fix" it. But I do want to follow up with the drivers idea of yours.

GA = Graphics Adapter (video card)

you've apparently found your prob., i.e. bad cable. until repaired/replaced the fix you've found may not hold too long.
yep, you could at least try the re-install of the drivers, can't hurt, still don't think it'll last long tho.
changing your refresh rate just alters slightly the output sig. to your monitor. bottom line, there's no way software can repair your damaged cable.

I understand. But, when I put a different CRT monitor into the system with a good cable, I still got the vibration on-screen at 75 Hz. And when I hooked up my 'defective' monitor to a friend's PC, there was no vibration on-screen. So I'm assuming that the problem's in the box.... Any comments? Thanks.

P.S.
I just reinstalled the Nvidia driver, and screen still vibrates at 75 Hz, but again not at 60. Maybe this is as good as this system gets.

Does your monitor have an 'Auto Adjust' button, or in the monitor menu? Look for any buttons on the side of your monitor, and try to find an Auto-Adjust button, or the menu button. Then use the volume +/- buttons to move between the menus to find an Auto-Adjust function. Often called 'Auto' for short. Try this to see if it make any difference.

Another thought, have you tried a different GA?

Problem is finally solved, as of 4/7/08:
Friend installed a new graphics card, and monitor vibration at 75 Hz is gone!
Thank you all for your advice and comments.