In task manager, check which process is using processor excessively and kill that process....

Run task manager (control alt delete should show you the option). Then click on Processes tab then click on the column called CPU to sort by highest CPU usage. That's how you find out what is eating up the most CPU. Depending on what process it is then you take further steps.

 Thanks guys, 

I dont see any programs consuming unnecessary CPU usage, however do see a lot of SVCHOST.exe

Is it the one which is making the laptop slow...

HELP HELP 911

 @Mula: 
Which browser do u use?

AE

Dude, you need to see the processes from all the users. There is a check box called "Show Processes from all users". Check that check box and now check to see all the processes which is consuming high CPU usage. If possible post your screenshot of task manager

 i5 processor, 6GB ram bhako computer ni slow bhayo re?! kasto application haru chalauchhau bro timi? mero 2 yr purano laptop (4gb, core 2 duo) ajhai kinya dinko jasari chaldai chha! tara ma normal user ho i.e. a lot of internet and some office 2007 tools, that's about it. kahilekahi game khelinchha jhyaau lagya belama, ani halka photo editing softwares. if you use heavy duty video editing softwares and large games like COD, your laptop slows down but 100% CPU usage ta hunu naparne. here is one simple but very effective tool you can use to boost your laptop speed:
- open task manager
- click on services
- at the bottom-right of the window, click on services
a new window with a list of programs in your computer will open; go through the list and right click on any that you don't use and open the properties of the program and choose either to  disable the program or manually start the program. disabling program will disable it until you enable it again. choosing to manually starting the program will keep it disabled until you start it later. the list will have a lot of things you don't know about. disable everything you no longer use. choose to start manually for the programs you use rarely, keep programs you use frequently sucha as: antivirus, system services, and others like web browsers, adobe reader, etc automatic. it'll reduce CPU usage and increase speed.
also, when you buy a laptop, the company (esp. HP/compaq/Lenovo) will send it with bunch of useless softwares that are just for their advertisement/promotion; wipe 'em out if you have any because they just slow down your machine.
download registry mechanic or similar software (from a reliable source: cnet.com ) and scan your computer, remove/repair old registries. 
if you have programs like yahoo messenger, skype that start automatically when computer starts, disable automatic start.

i guess that's all i have for now. 

-Jantare

Thanks guys

1) Alterego - I use Chrome.
2)ihateamerica - I checked the users, there is none except myself.
3) Janterai - hallelujah!!! mucho gracias senor, i have got HP and now removing all those crappy softwares which I never use. Just now installed CCleaner. I hope it works.

 one more thing are all your rams the same or have diff speeds? also check if all of the rams are present in your system info. right click my comp and then properties.

Run windows recovery from your recovery hard drive and re-install windows. Then install programs only you need. Back up your files b4 u do it.