Depends on the reason for the sluggishness. If the internet is slow but everything else works fine: Try downloading "Spybot Search and Destroy" (freeware) and searching your computer for spyware which may be slowing down the connection. Also run a virus scan using your antivirus program. If this doesn't work and there is nothing else running (p2p downloading apps etc) which could be using up your bandwidth you may need to upgrade your internet connection. If everything is slow, applications load and run slowly: Uninstall any programs you don't need anymore using "add or remove programs". Run a virus search using your antivirus program. If this doesn't work then at a time when your computer is running slowly open task manager by pressing control alt delete. Then by using the performance and processes tabs determine whether it is your CPU or memory which is maxed out so to speak. Then look into upgrading either your CPU (central processing unit) or your RAM (also called memory or system memory). Unfortunately if your computer is an older model either of these upgrades may require a new motherboard, which could cost around 40-100 pounds depending on the specifications. I hope this helps, if you need more help just comment. +2

Everything the dude above me said. Also, check your registry and try defragmenting your hard drive.

I say sweet thinks to it. Unless it's running Windoze.