TF2 FPS dropping down to zero

Problem:
When I first play the game, the performance is great (over 100fps in spawn, at least 50+ in battles) but it slowly drops over time (around 15mins?) until it falls below 10fps even in spawn.

I am currently using an Dell XPS M1210 with the following specs:
2.0GHz Core 2 Duo
2GB RAM
NVidia 7400 geforce go turbocache
80GB 7200RPM HDD
32bit Windows Vista

Now, I have all the settings in Team Fortress 2 on the lowest for every video setting and resolution, used config files to make them even lower and launching using directx 8.1. I even tried the dual core option, which increases my fps, but does not stop the inevitable decline.

Here are the things I've tried:
Updating GFX drivers (have tried old, 163.74, and new drivers, 174.93, although the new ones cause me to BSOD randomly in windows)
Setting in NVidia Control Panel to performance
Lowest graphics settings
Lowest resolution
Config files
Dual Core option
Closing other programs
Defragmenting HDD
Scanning for malware

Not viable options:
Installing XP
Getting a new computer

Other notes:
CPU temperatures around 70s just after game exit
Normally 50s in idle, it is undervolted using RightMark
Sometimes fps does go back up a while after it goes below 10, but rarely goes back up beyond 20.
Laptop seems to be running hotter than a few months back.
BSOD's started after I upgraded to SP1 and upgraded video drivers at the same time.

I've pretty much included all the information I can remember, would be great if anyone can help me with this problem. I just want to shoot and stab some people in peace without taking 30seconds to turn around.

 

Have you tried cleaning the vents in your notebook? Visit the NBR Cooling Central for some extra info.

 

Indeed sounds like a dusty cooling system, tho that shouldnt cause frame detoriating only sudden drops. Try a 177.xx driver from laptopvideo2go.com (forums).
Also try reinstalling the game, cleaning the registry and hdd and defragging again

 

Sounds like overheating, agreed. Use HWMonitor to check your temperatures during low framerate times.

 

Thanks for the quick replies. I'll try getting a Zalman NC1000, it should work for the m1210 as the intake is at the bottom? Although the intake quite small...

I'll also try to clean out the vents once I find some compressed air.

As for the drivers, I think most of the newer ones cause my laptop to BSOD, which is why I went back to the older one (163.74).

Does HWMonitor show the stats while in the game? Valve games aren't exactly alt-tab friendly.

 

HWMonitor saves max/min temps, so you dont need to alt tab/use overlay