f12 in steam tooPerhaps it's something to do ith your interwebs?
Also, one way to take a screenshot is by hitting shift and the Print Screen button, or just the print screen button, and pressing Ctrl+V in Microsoft Paint.
Before you try it, try getting the beta HL1 update. You have to rightclick on Half Life, go to Properties, and under Betas select "Beta-Beta". See if that fixes it.Also making my own server there is the lag. If I reinstall the game?