It means bringing your CPU, RAM, GPU, or whatever else in your PC to speeds above and beyond stock speeds.
Every component overclocks differently, and every system overclocks differently.
Problems associated with it are burnt out mother boards, burnt out CPUs, burnt out graphics cards... basically anything that's overclocked might burn out. But if you're careful with applying voltage and monitoring temps there isn't so much to worry about.
Best way to get info on it is just googling. There's tons and tons of guides.
Don't let it scare you though, if you are conservative then it is perfectly safe, but like Wolfman23 said make sure you do your reading.
Post your PC configuration and we can direct you to a good guide.
actually my sys config is
Intel 945 PLRN MB
Intel 3.0Ghz pro
256MB 533Nhz RAM
80GB Seagate HDD
AOC 15.6 LED
I have read a small guide about overclocking and i se my ram clock speed from 533 to 667.before is changed 533 is taken in auto i manually set to 667Mhz and saved.my system boot up normally but after boot up if i open anything ex:chrome,ccleaner,any softs it is giving some error entry point not...(i forgot sorry).i tried this some times restarting the system.again i changed from manually set 667Mhz to auto 533Mhz.after this its working very fine.
if we sppedup clock settings u said any chances to burn.i want to know is when ever we speed up clock system performance has tobe increased.but why the software errors its showing.if any reason behind this pls explain me.
Instability. The RAM is set to be faster than it can handle. Like d1rty said, you'll have to try raising the DIMM voltage a bit. But you should google the exact RAM code (usually labelled on the RAM stick itself) and see what it is rated for.
That system seems very dated. Again, I agree with d1rty that you should look at increasing the amount of RAM. What OS do you use? If it's XP or newer I'm very sure you're maxing the RAM and running off file paging, causing extreme slow down.
Yes as u said im using XP sp2.but in bios if i select auto it is taking 533Mhz.if i select manually set it is giving 2 options 533 and 667.there are no other options to adjust voltage.wolfman said raise DIMM voltage a bit.i didnt get his point.i look bios for this option i didnt get it
Yeah it just means the board isn't really meant for overclocking. It says 533 and 667, but technically what it means is you have a choice of two FSB:RAM ratios... If you raise your FSB a bit, it'll still say 533 and 667 but in reality those numbers are high, as they're dictated based on the FSB.
I guess it'll auto volt it... if it runs stable with 667 then I guess you're fine. You might want to check CPUZ to see what timings it's running the RAM at and of course whenever you change clocks you should do stability tests.
Anyway, like I said before, more RAM will give you way way more benefits than a small overclock.