Acer 7520g problem

I already posted my problem as a reply to another thread, but got no answer, so please dont mind me creating new thread, couse i just cant find solution anywhere on the net.

For 10 months now I have Acer Aspire 7520g with Turion TL-58 1,9 GHz, 2 GB RAM and dedicated GPU 8400M 256 MB with turbocache up to 1024 MB. This laptop is running licenced Vista Home Premium with SP1.

I mostly play WoW on it and in a first few months i didnt have any problems. I was running this game at 25 fps on medium details. I stopped playing WoW for 3 months and I didnt use my laptop much in that period. In the meantime I installed every update on Vista including SP1.
When I started playing again i noticed that I have a very annoying problem. Every few minutes processor gets stressed and its working at 100% usage. It goes on for 20 sec or so, and it works normally again. In those 20 sec my framerate drops on around 5 fps and game is unplayable. Task manager does not show anything strange at the processes tab. I installed some AMD software like AMD power now or Dual core optimatization but nothing helped, and it shows 100% usage of both cores at the critical period.
This problem is constant now, not just with WoW, i got it yesterday when i played some flash games and music on WMP.
I have this problem no matter what i do on my laptop (its less noticeable when i surf the net or work in MS office, but its there), and no matter is the laptop just turned on or its working for 5 hours (at that slow down period i notice a processor cooling fan speed change, but i doubt its a overheating problem, becouse both cores work on, for laptop nice, 65C after few hours of playing).
It repeats itself every 2-3 minutes, and make my laptop very annoying to use.

Could it be that some update is couse this problem, maybe SP1? Shall I try to reinstall Vista without SP1? There is a lack of XP drivers for my laptop so i dont know is it possible to run it. Or shall i just take my laptop on service? I have 2 more months of warranty.

Tnx for your help in advance, every suggestion is welcome.

 

ugh no xp drivers? even hp does this! vista or freedos, or use xp with problems! try calling acer customer support... try reinstalling, i dunno! is there a way to downgrade sp1? i think there is, try that maybe?

 

Tnx for reply.
Unfortunatly, in my country there is no Acer support that I can call. I found most of the XP drivers, but I cant find one for Ethernet card/Lan card (did find one but not on Acer site and Im not sure is that the right one)

Anyways, after all it seems that it is a overheating problem (i`ve tried to cool the laptop with the living room fan pointed at the laptop), and for 10 hours of play problem did not happened.

What can i do now? I cant accept that this overheating problem is normal becouse of high temperatures over the summer. Shall I take the laptop to service, can I do something by myself? I tried to increase cooling fan speed but there is no such option anywhere (tried bios, some fan controlling software).

What would you do if u were in my position?
Cmn guys, post suggestions, Im wide open for any opinion.