first thing first...make sure you have the latest drivers of all hardware especially the video card and that you have the hl update 1.1.1.0 (if using hl) then check if you have esf running on opengl video mode....it works best with this but some cards can handle it, but if you have like an nvidea or rage card it should work. To check this go to options->video options-> advanced options and check if opengl has the bigger font (or on won it was like this) go look for it shouldn't be to hard. If it is on opengl and it still does the same then you should go to the console and type cl_fxquality "1" then the extra stuff, like rocks flying up and stuff like that, grows less important and this can maybe fix your powerup shutdown if you have a slow computer. If this stil doesn't work then you should reinstall half-life/steam and ESF. Most probable it is the opengl thingy...there is probably a sticky about it in esf section or help section.