Up until recently my TF2 ran max settings 150+ fps in multi-way combat etcetc

Recently... I get 10-40fps, it's not playable and I get the same fps if I go to minimum detail. I've tried fps configs, (chris'), uninstalling and re-downloading TF2, tried different DirectX versions;
(8, 8.5, 9 and 9.5)... getting my original 150+ fps that i'd previously get with DirectX 9.5 with the 8, but I love my sheens too much to stay on 8.

Anybody had anything similar or any advice?... Thanks