yeah, like Loyal said, get rid of background programs. Also, try and close any unecessary processes that may be running at the same time. Believe it or not, sometimes, even when you close a program, and think it's closed, it may still be running. To check, go to the task manager, process tab, and look for anything that looks absolutely unecessary, and end the process. CAUTION: DO NOT DELETE ANYTHING THAT YOU ARE NOT SURE OF. IF YOU DON'T KNOW WHAT THE PROCESS IS, DO NOT END IT, YOU MAY SCREW YOUR COMPUTER UP. ONLY CLOSE PROCESSES THAT HAVE ABSOLUTELY NO IMPORTANCE, SUCH AS A GAME.
Tips: In most cases, a process takes on the name of the program it originally ran from, so if you see lets say Gunz.exe, then you can probably close that, because that's probably just gunz.
Last warning: DO NOT DELETE explorer.exe. It may seem to you that it's just your internet explorer, but it's NOT. I'm not exactly sure what it is, but I do know that if you, all your desktop icons, and the bar at the bottom of your screen (the one with the start button, and the time, and task tray in the bottom right), will disappear. Now, if you accidently end the explorer.exe task, simply open up your task manager, which is ctrl+alt+delete (BIG NOTE: Notice I say DELETE, and not BACKSPACE. Please do not confuse the two. The delete button is usually grouped on your keyboard with the home, end, and some other buttons.) and select the task manager. Then go to the process tab, and click File> New process. Then type in explorer.exe,and you're done. (this can probably be used with any other process you accidently delete).
Sorry for that big blob of text, but I just have one other thing to suggest. If possible, could you post a screenshot of your computer specs? It might also help us as to why you may be lagging. You can, of course, using paint or what not to block out anything you don't want us to see, but yeah, if possible, that could help us.
