How to reduce lag?

Should I really be having lag?
I have comcast w/ powerboost, wireless internet(belkin) connecting to a router whos signal varies from 36-54 mbps mostly 48/54. I have 2gigs of ram on XP, a geforce 5500 graphics card(yes I know it sucks) and I just reinstalled windows for the first time in the 6 years I've had this computer. Thus I have nothing from the necessary drivers(keyboard,speakers,graphics card), and under 10 programs installed.

Thanks,I may try it.

im testing thid out now

hey man i use to lag like hell but this helps!!!! trust me its awesome

heres the link

http://www.iobit.com/gamebooster.html

it closes un used programs and things you dont need for a better gaming experience

Yup, I use Game Booster myself.

I added it into original post.

Jordan thanks for the game boost link it has helped allot. Although I still have some lag here,and there it helped me allot.
7/10

Thank you very much for the information. It surely helps. You don't need to get a new PC if games lag. Just turn down the settings. The graphics may look ugly, but there's no other go. I agree with you.

GameBooster, it's a good tool for saving memory closing unneeded to work Windows processes. In my case, I'm saving more than 50mb of RAM.

Thanks a lot for the Game Booster link, it really helps when I play Left 4 Dead 2 for my PC. Also, Fallout New Vegas singleplayer. Thanks in advance!