I started overclocking a few months ago to try and get my games to work better and my apps to load faster. After experimenting with hardware overclocking and have some fun (and some disasters), i found i could make my medium level graphics card put out a few more frames per second, my cpu (pointlessly) and the Ram, i could increase the throughput of the computer quite significantly.
I started University recently and i study operating systems software as part of my course, I realised that id tweaked my hardware but not my software? Now rather than go in depth, ill give some basic pointers on how to get more from windows XP, this sort of optomisation is relativly hazard free.
How To Speed Up XP:
The desktop is constanly using up resources of the system. If you have a cluttered desktop, your computer is constantly wasting resources putting out all those pretty icons your probobly not looking at. Furthermore, if you set your desktop theme to "Windows Classic", itll significantly free up resources. This will obviously be more noticable on older systems, but if your pernickity like myself, youll feel it in your games.
This can be tricky if your not familiar with the concept. A process is a program, even if you cannot see it, its still a process visible by pressing ctrl-alt-del and clicking the process tab, there are usually 3 types of process System, Local Service and User, we are concerned with the last one. User processes are processes started by you...well usually...anyway, the way you can save some resources here is by shutting unneccesary ones. What ones are unneccessary? well that depends what your doing, the names are usually self explanitory (iexplore is internet explorer). The best way to find out what processes you need is to shut down the ones you think are not, dont worry, if you hit an important one it wont damage your system, you may lose your taskbar untill you restart or something silly.
I dont want to go into advanced ways of speeding up XP, as i find the upper most to be most useful, but if you want to tweak XP some more. Heres a good source Extreme Tech