Suggest the major frame rate problem with graphics is due to the sub-standard video card you have. Most laptops are configured for business use, not games, and games are the most resource hungry of all!
Check with Gateway to see if they have a video card upgrade for the machine (something with an NVidia TNT2 chip preferably, you do not have the CPU for anything more powerful) or if it is incorporated on the motherboard (If so, you are stuffed) That should fix the problems with the games.
I am not familiar with the sound chip, but again it may be some cheap proprietary thing mounted on the motherboard. Check you manual on this.
Generally, I would avoid anything with motherboard mounted sound or video. They are mostly inferior chips, and you are limited in the upgrading choices later on.
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When all else fails, read the manual!