I have a emachines computer. I turn it on and hear clicking and the fans, like it is running fine, but the screen says no signal. It is xp and the harddrive and power supply are fine. What is wrong with my computer? Pls answer I have tons of important info that I need to get off of it.

A dirty hard first clean all of the dust from your computer using a fine air blower using a vacuum cleaner with no metal piping you might short your motherboard out if metal touches anything or a fine air blower from a compressor making sure there is no MOISTURE in the air line then give the hard drive a firm tap on one side to free up the read arm you could run the check disk utility Click start run type cmd then type chkdsk/r which willscan for and attempt to repair any bad sectors then defragment your hard drive don't do anything while the chkdsk utility is in progress any input may damage your computer
WARNING: Before you start troubleshooting remember that you are dealing with electricity that can KILL. http://www.kitchentablecomputers.com/static.php - rules Test all power and data leads that attach to your hard drive IDE,SATA the leads from your (motherboard to your hard drive) make sure they have secure dust free connections and are not faulty if its a 40 pin flat ribbon type it will be the first to fail make sure all leads that are attached to your drives dvd\cd 3 1/2 inch floppy have secure connections and are not faulty even something as small as a faulty electrical fan and its lead can cause you problems computers need all power and data to continue through every working device and to have an end so any faulty leads will end up with a computer error Make sure your graphics card is securely seated with no dust built up or in the socket if you remove your graphics check the socket to make sure its dust free Restart your computer then reinstall it this should activate found new hardware wizard Check the vga lead for secure dust free connection or try another vga lead. Hope this helps.