Computer shutting down

A business has 3 computer/registers at their checkout. When any of the registers printed an invoice the middle computer would shutdown. Now whether a computer shuts down or shuts down and restarts is important. The former is always a hardware issue and the later can be a hardware of software issue.

I initially thought that the middle computer was connected to the printer via a USB port but the printer was on the network. Unlikely but there could have been problems with IP addresses and a faulty Network Card (NIC) in the middle computer.

I had a closer look and noticed that all three computers have a UPS attached. UPS stands for Universal Power Supply and these are generally large batteries and when it detects an outage it will switch over to use the battery. More expensive UPS devices use the battery constantly and condition the power so it stays at 240Volts and 50Cycles (In Australia).

UPS devices do wear out however and I think that what was happening was that the power drain on the power circuit when the printer starts was tripping the UPS over to the batteries. Unfortunately the batteries were well and truly dead and so the computer shutdown.

I temporarily connected the computer into the power and it must have worked as I haven't heard a complaint.

Wet laptops

Laptops get all kinds of things spilt on them and they come in regularly. I recommend the following to give the laptop of fighting chance to survive a dunking or a spill. First is disconnect power and get the machine stopped as soon as possible. Don't worry about saving anything, hold down the power button until the laptop turns off. The next thing to do is to flip the laptop over, remove the battery and sit the computer upside down but open. The laptop will look like an A. This lets the fluid drain away from the motherboard.

When the laptop arrives I then take off everything I can from the bottom (RAM, Battery, HDD and DVD drive. I then remove the appropriate screws from the bottom and take off the top strip and the keyboard.

You can usually see the motherboard at this stage. I then hit the laptop with a hair dryer. I still leave the laptop for a day after this to make sure that all of the laptop is dry.

If the laptop has had coke or a sugary drink spilt on it, I usually then strip the laptop right down as coke will corrode the laptop. I then wipe the motherboard down with alcohol to remove all signs of cola and then again dry the laptop thoroughly. I usually can see at this stage if anything has blown and would need replacing.

Computer Not Booting (An easy one for a change)

A customers computer would not boot. It came up with an error NTLDR not found press Ctrl-Alt-Del to reboot. The harddrive wasn't making a noise which was good for a change and could be seen in BIOS. I set up BIOS to boot from a BART partition on my thumb drive. Most BIOS have two boot places. One to pick the device type order and another for the Hard Disk device order. When I restarted the computer would not boot from my thumb drive.

I went into BIOS again and notice that the first device to boot was the USB HardDrive. I changed this to last position and then booted again and the computer booted beautifully.

Computer reboots every hour at the same time

Most times technicians fix a problem but do not really know the cause. A customers computer was shutting down. The first thing to ask is if it reboots itself or does it just shutdown completely. In this case the computer (A Vista machine) restarts. If a computer shuts down completely then it is a hardware issue. If a computer restarts then it is probably a blue screen (BSOD) that flashes by too quickly to see.

To investigate the blue screen the first thing we do is look at the system event log. The log most times captures the stop code of the failure. A good reference for all stop codes is http://aumha.org/a/stop.htm. Also we go into the system settings to stop the automatic restart. This lets the bluescreen remain on the monitor long enough to get some details and hopefully point to a file that is causing the problem.

In this case there was unfortunately no event log item for the failure just a note saying that the last shutdown was unexpected. What was interesting though was that the failures occured hourly at 43 minutes after the hour. this definitely looked like a software issue. I then checked the scheduled jobs for an hourly job without luck. I then looked at the power settings (Vista doesn't have a good relationship with recovering from standby mode) but there was no hourly settings. I even rang the supplier of the software on the computer and they didn't have an hourly process.

As it looked like it was an hourly setting, I just did a system restore back to a time prior to the failures occurring and the problem has so far disappeared. My guess at the moment is a virus but unless the problem reappears I'll never know.

Lights on but computer would not boot

Ahh Saturday. This computer's lights came on but it would not boot. We can't test motherboards directly but we can test them by a process of elimination. First I remove all peripherals - Memory, data cables to the drives, graphics cards and any other cards. Then I attach a new power supply (PSU) to the two power connectors on the motherboard. 80% of the time I'll get the computer to boot. This case however the motherboard was dead and the customer decided she would rather buy a new computer.