How to reduce Windows XP computer boot time?

You could try profiling your startup time to see what exactly is taking such a long time. This will help you better figure out what to reduce. There's a question regarding this on SuperUser.

"The quickest thing you can do is to click Start then run and type ""msconfig"" go to the Startup tab and disable everything. Reboot and reinstate them one by one until your computer is faster - by using this method, you will be able to see what is taking longest.

You can also go to the services tab and disable there. Services such as AV programs are usually the most to blame for slow start up times.

If you want more control over the startup and see exactly what is running from any location on your system, I highly advise you use the Autoruns program from Microsoft Sysinternals."

"After cleaning up run either:

rundll32 advapi32.dll,ProcessIdleTasks

or

defrag C: -b

Both defragment boot files in logical order destroyed by each Service Pack.

You might want pagedfrg.exe from Sysinternals to make registry into one fragment and contig.exe to defragment disk structures like MFT$."
"After cleaning up run either:

rundll32 advapi32.dll,ProcessIdleTasks

or

defrag C: -b

Both defragment boot files in logical order destroyed by each Service Pack.

You might want pagedfrg.exe from Sysinternals to make registry into one fragment and contig.exe to defragment disk structures like MFT$."