>Another often overlooked cause of problems is bad AC power. If the PC is on the same circuit as a photocopier, coffee maker, arc welder (don't laugh!) get her to try a UPS, or, at least get an electrician to hook up a voltage logger to the output.

Al;

We had a major data based application for our corporation’s test and measurement equipment and contractual requirements. Hundreds of millions of dollars in equipment and government contracts were involved as well as commercial accounts. Problems of a serious nature could mean the jobs of thousands of people.

All was well until... The company just installed three huge ovens (over 100 feet long and ten feet high) used in the ceramics division of the company. The ovens were controlled by SCR's and had SCR power supplies which created "quasi sine wave" voltage. That is the SCR's broke the sine wave into four quadrants and created a result sine wave which was not very accurate.

We put an AC line monitor (with log graphic recorder) on the line to determine the source of the problem. The switching point of each SCR created one hell of a spike on the AC line through out the plant. Such devices will tear up anything resembling data. Even a simple SCR light switch on the wall can create such problems to some extent. And our friend the Laser printer can create “interesting” problems also.

Another source of problems is the switching power supplies found in PC's. When these get old they can tear up data.

I guess my previous profession of electronics engineer helped me to better understand such problems. Now if I could just figure out how to use the remote control on my new VCR! :)

Tom