First thing you need to check is your network cable. There are cases where twisted or kink-laden cables (caused by office wear and tear) cause PCs to self-reboot. The simple solution is to replace the cable. I’m sure the supplies personnel in your office would not begrudge you of such a simple request. Or if you’re the one shouldering the cost, I assure you that your wallet won’t feel the loss.
If it isn’t the cable, then it must be the network card. Experts from Answers that Work suggest the 3com network card for servers. Just ask form your technician regarding this.
Cause number 3 is a faulty Uninterruptible Power Supply or UPS. This usually happens when the PC’s UPS has outlived its two year warranty. This happened to me years ago when I was working on my undergraduate thesis. My PC would self-reboot at the most inopportune times. The cause of my agony was a simple faulty battery. The best solution to this problem is to replace the UPS when it turns 18 months old. This will prevent having your work interrupted by a sudden reboot only to find out that you had not saved any of your data for the last hour.
Source: Answers that Work

Prevent your computer from crashing by regular maintenance. One thing you can do to clear disk space is to run the disk cleanup option .
Just follow these easy steps!
Open My Computer.
Right-click on the hard disk drive that you want to recover disk space. Let’s use the C: drive as an example, since it’s the most ‘abused” drive anyway.
Next, click properties. You will the General tab/ Just click the button that says Disk Cleanup. It is next to the pie chart. Windows will now scan the computer for all files available to clean up.
Last, when already in the Disk Cleanup window, check all of the boxes that are taking disk space EXCEPT “compress old files“.
Click Ok and then Yes if you wish to proceed.
One thing to remember when performing a disk cleanup, there is an option to compress old files in your hard drive. It is strongly recommended that you don’t. Besides, Windows 2000 and Windows XP keep the files that are necessary to uninstall the updates (which could accumulate up to 1 gig of wasted disk space) that have been installed on your computer.
So the electrical connection is not the problem. Let’s move on to the Power Supply Unit or PSU (unless your PC utilizes a UPS instead. This will be covered in the next post). The PSU is the most common cause of self-rebooting. The best way to troubleshoot this is to replace the PSU (TIP: When replacing a motherboard, also replace the PSU). There are good quality PSU out there and they come in relatively cheap prices. Do not attempt to replace it yourself if you have no idea on how to do it. Better take your PC to a repair shop.
Source: Answers that Work
Once in a while, we experience connectivity problem — say, we cannot connect through the web or sending and receiving email takes time. We assume that this problem is because of system’s connection to the Internet has somehow failed. When this occurs, you can usually determine the exact nature or location of the problem with a series of ping tests.

Oh yeah, a problem that always occurs. Don’t panic, my dear friend. If a message stating this error pops on your screen, then it means that you have one of these problems:
Your Integrated Drive Electronics (IDE) cable is loosely connected. Check the IDE cable and make sure if both ends are fully plugged in.
Another problem may be that the IDE cable is reversed. Yes, this can happen. Check if one or both ribbon cables are actually connected in the right way. What right way? Pin 1 should align with Pin 1 on the drive. Just look for the side that is incorrect and flip it around.
If it’s not the IDE cable, then it may be your power supply. Check if you have power to the floppy drive.
Another variation of the problem is that the drive is probably attached to the wrong side of the twist. The twist reverses voltages and is found between the two drive connectors of IDE cables. You can swap the floppy drive by enabling it in the BIO. It is simpler though to just attach the drive to the other plug.
This part of your computer system converts your regular household current into low DC voltage used by the computer. When this component fails, there is simply no activity going on with your computer. Always inspect the Power Supply for any damage. Double-Check all connections and don’t permit the simple pleasure of turning on your PC and everything works just fine.
Power Supply units have become quite complex in today’s computers with prices to match. High-end brands tend to have a lot more protective circuits and have more ‘oomphh’, allowing them to supply more power when the computer needs it during high power drain situations. If you aim to use your computer for regular use, then the power supply that came with your computer’s casing would suffice, lasting for years before it submits to the strain of use. For extreme gamers and other applications such as video editing and such, you might want to ask for a more powerful power supply unit that can give constant power all throughout but be sure to bring your credit card for they can cost a lot…. A whole lot!
Soapalyzer is a device for consultants and software developers with acute problems in a production environment. It assists to get to the bottom of application bugs and performance bottlenecks in live SOAP Web Services. Unlike other Web Services analysis tools, Soapalyzer can be positioned in a timeframe of minutes, instead of weeks.
One main problem that you face is by re-booting the computer without any warning. All information is lost and it seems as though this happens at the worst possible time. You need to repeat some workloads as well. Booting errors when the computer first start’s up is another indicator of this component going on the blink.

When you repeatedly double click a program icon but with no results, the application may have hung.
The way to solve this in Windows XP and 2000 is to right-click the Windows task bar and click Task Manager on the menu. Next, pick the Processes tab in the application window and click the list box column head labeled Image Name to arrange the applications running. Locate the application you want to open. Right click the offending applications and choose End Process, then click OK. Do this again until all programs close. Close the Task Manager and begin the application once more.