Is
Your PC speed slow, and want to be faster?
It depend on for what you are using your PC. If for writing can you improve your typing speed
http://www.keybr.com/ Recommended for anyone doing serious work at computer.
Learning more about the software you are using such as shortcuts can also increase your efficiency.
If hardware is slow, such as memory, hard-disk and graphic display can it be overclocked a bit but it is mostly limited effect type 10-30 % and can be a bit risky, if you do PC work that are important to not loose.
If it is more related to software limitations and an operative system with to much bling included, replace it.
Installing a more power effective operative-system, requiring less memory and hard-disk bandwidth will get more done in shorter time. I recommend
http://www.drdos.net/download.htm which I can make even a real old computer to fly. DRDOS have network support and a free web-browser exist. Immune against most types of online virus and trojans. Booting is very fast. I use it my self.
Removing existing unneeded software running in background and reduce screen resolution are quick and simple tricks. If windows, check list in "taskmgr.exe", there are a lot that can be removed, if you not use all functions.
Installing older versions of existing software can also improve speed.