I am not el but I will add my thoughts here.
There are several reasons that computers take time to boot. Among them are the hardware items that must be recognized during boot up and the software that is loaded as Windows starts.
You didn't say which OS you are running. I will assume that you are running Win98, WinME or WinXP so that I can give you a hint. Go to Run in the Start menu. Then type in "msconfig" in the box that pops up after you choose Run.
Click on the "Startup" tab in the Window that opens. Notice how many programs are checked. All of these start when Windows starts. You may uncheck some that you don't need to have running in the background. Many of these will be seen in the Tray which is next to the clock in the taskbar at the bottom of your screen. If you have a whole lot of little Icons in the Tray chances are you can ditch a few.
Experiment by turning them off one at a time and rebooting.
Some that you may not want to turn off are listed on web sites that help with this very question. If I have time I will search for some of these sites and post below. You don't want to turn off your antivirus program and/or your firewall.
The other major category is hardware recognition. There are some tricks there, too. If you are handy with BIOS changes you can disable the ports that you don't use (unused serial ports) and stop the BIOS from looking for IDE drives that don't exist.
Disabling or setting these hardware devices to NONE can sometimes save boot time.
If you are running WinXP there is a utility to shorten boot time called bootvis.exe. It only works with XP. It can be found at:
http://www.microsoft.com/HWDEV/fastboot/