Windows 7 - Computer lagging?

I just instaled windows 7 and i wanna play league of legends... so i got a good pc for lol low details : 1gb ram, AMD athlon(tm) 64 processor 3000+ 1.8GHz,nvidia gforce 8800 gs
... and when im playing counter strike with teamspeak 3 fps is "high-low" just falling and raising ... can somebody help me?.. and on facebook whem im scrolling down its kinda laggy -.-' ? what should i do?

EDIT: how can i see is my computer 32 or 64 bit?

1gb of ram is marginal for running Windows 7. 4 gb installed is about the minimum I would recommend these days. More if you go 64 bit. The rest of your components are a bit weak for gaming, but you'll get the best return on your $ by upping your ram and it should address your scrolling lag.

It's your operating system that determines 32 vs 64 bit. Go to Control Panel/System and Security/System and it'll tell you your system type. If you installed a 32 bit copy of Windows 7, it'll indicate "32 bit Operating System", etc.

You can install 64 bit Windows 7 on an Athlon 64 IF you use a 64 bit Windows 7 install disk.