Check all external cables to make sure that they are firmly attached.
Run a virus scan from a boot disk.
If your computer does nothing at all, no lights, fan, or anything, your computer may not be getting power. Disconnect & reconnect the power cable, and check to make certain that the electric outlet is working. Make sure that the voltage switch on the power supply is set to the correct voltage (110 for most settings). If this doesn't work, your power supply may be bad. I would recommend visiting the nearest computer repair shop to get this checked out, unless you feel confident enough to try it yourself.
If you get an error message such as "No operating system found", "No boot disk", or "Insert boot disk", the computer may not be seeing your hard drive. Normally, there is a BIOS setup that can be entered by pushing the delete key, F1 key, Alt+s, or some defined key combination on bootup. Enter this setup, and see if there's something such as auto-detect hard disk. If you find this utility, run it to redetect your hard drive. Try it out. If there is no utility present, you may have to open up the machine, and look at the hard drive. Most drives have a model number and manufacturer printed on them, and you may have to look up the manufacturer on the web (usually www.manufactorername.com). Find the CMOS settings for the drive, and input them. Still having problems? Try booting from a floppy boot disk (you can make one by typing sys a: with a disk in drive a: at the dos prompt from another computer). See if you can read anything on the hard drive (type c: <enter>, dir <enter>). If you can, your system files have probably been corrupted. You will need to get your original system disks, and reinstall your operating system. (You can also try just booting from the disk & typing sys c: at the dos prompt).
If the computer starts to boot, but
locks up after the "Starting MS DOS" or "Starting Windows 95", look for
solutions under the appropriate operating system below.
Printer doesn't work, spits out garbage:
Turn off printer, turn it back on.
Try disconnecting & reconnecting
printer cables.
Try another printer cable.
Reinstall printer driver.
Try running scandisk to check your drive for errors (right click on your hard drive under My Computer, click tools, click check for errors).
Go to a DOS prompt. Type "set". See which folder is set as the temporary folder (TEMP="..."). Reboot into MS-DOS mode, switch to this directory (cd\tempdirectory), and type "del *.tmp".
If netscape is crashing, try deleting the contents of the cache folder (usually c:\netscape\cache). This cache can fill up, and possibly get corrupt files which can crash netscape.
If one program is consistently crashing, try reinstalling the program, and checking with the software support to see if there is any updates/bug fixes.
Computer with a network card won't shut down:
Go to Start->Settings->Control Panel->System->Device
Manager. Find the network card listing, and click properties.
Click update driver, do not detect, network adapters, have disk.
Insert your network driver disk and reload the driver (it may be in a directory
such as win95). If this doesn't work, try going to the companies
web site (usually www.companyname.com), and looking for an updated driver
for the card.