Tell someone that if they go into a shop and ask them anything about drivers and have them look at, know that when you walk away, they will be laughing at you. I don't mean that to be nasty, but there is no need to take the Pc to a shop or worry about the safety of updating.
I'm worried that you have perhaps never updated them before!!!
As Pacov said, Video Card drivers are perhaps your most important ones to ensure they are updated. The rest, well if your running Win7, then you probably already have the best drivers installed, unless you have some very specific devices attached.
Check your motherboard manufacturers website for downloads for your particular model. Most are just installers, no need for fancy work here.
Please though, don't be fooled into buying software that will scan your pc and find drivers and install them for you. they are not needed and many are closer to maleware than actual helpful apps.
PS - Up to date drivers, or better put, not up-to-date drivers can have a huge negative effect on your gaming. Always ensure your video card is running on the newest driver and only ever download it from the chipset manufacturer. (thats not gospel of course, but doesn't hurt)
