Lag spikes

[thegamer]

Hi i recently started to have lag spikes with my computer I would be playing a game as simple as league of legends and occasionally it would lag it got worse and worse to the point where it would even lag watching youtube. These lags come in about 10-15 second intervals and I have no clue why. My cpu usage will hit 100% during these lags and only about 35% of the usage will be accounted for.

running m17Xr2
intelcore duo 2.4ghz
4gb ram
64 bit windows 7 (now vista)
nvidia 9400m graphics

I tried wiping my computer back to defualts with alien respawn 2.0 and now am on vista and still having the same problem. I have done scans with avg, avast, ccleaner, malwarebytes, and spybot.

Any suggestions are greatly appreciated

 

[logiccs]

You need to find out what program is causing the spikes. before it lags, open task manager (ctrl+shift+esc) and select "Proccesses", sort the list by CPU.
Now carry out a task that you know will increase lag or just mess about for a bit with task manager in site. When you see it slowing down, check the task manager and write down the top 5-10 applications. It may be obvious ("Skype.exe - 100") or it may take some working out. Post the results on here and i'll see if i can help
PS - I found AVG to be a resource hungry application and i'm assuming you don't have the above programs all installed together?

Also, can i check is your laptop quite old? Can you hear a loud exhaust noise or no noise, and can you feel alot of heat? If so, the exhaust fan may be no longer working (causing the CPU to run too hot and underclock the CPU) or be clogged with dust and muck (causing it to overheat and underclock the CPU)