for those wondering -
The default is 0 -> off - set it to 1 and ctrl-alt-delete will reboot the box for you.
browsers "locking up" your desktop? -- go get noscript and use it aggressively - the single biggest issue I've ever had with a browser was a period of time while doubleclick were firing an audit (IP address, cpu type, mem, window size, screen size, site cookie list) that basically returned void data for cpu type on linux, which forked and looped. Hit a site calling that JS and it could eat almost a gig of ram in less than a minute. I had a long, loud, vigorous discussion with the DC rep the company had at the time. His comment was "Well, make the file readable, our script requires that information to function correctly".
The biggest "slowdown/laggy/bad response/bizzarre behaviour" issues I've seen with most linux installs come from a hard drive, slowly dying, and running out of spare blocks. Usually windows will chug along fine in this case, but you will find that it too eventually hits the same behaviour -- just later after more of your data is gone.