My left 4 dead 2 is slow any lags in single player and online why?

my specs are: * AMD Athlon II X4 quad-core processor 620* For true multicore performance, optimized to deliver the benefits of Windows 7. AMD PowerNow! 3.0 and Cool’n’Quiet technologies for a cool, quiet and energy-efficient PC. * 8GB PC2-6400 DDR2 SDRAM For multitasking power, expandable to 16GB. * Multiformat DVD±RW/CD-RW drive with double-layer support Records [...]

i saw a web 2.0 site contains a single html page which contains all css styles of their design.?

i forgot the url.. any one remember ? its like a style guide or something.. listing all elements and class in a single page.. h1, h2, h3 ..class=”footer””..