New Graphics card? update your motherboard? Latest version of Java? Depends on the game

Some simple things to do are:
Clear up programs (delete anything you don't need)
Use "Disk Cleanup" and "Disk Defragmenter" both of these are found under Accessories on Windows.
Don't download anything claiming to "SPEED UP YOUR COMPUTER IN 2 MINUTES!!!", that's how you get viruses.
If you have a desktop you can try upgrading your RAM, and other accessories. (Google is your friend on that one). Or even opening up your tower and cleaning it, will help!
Also you can adjust your game's priorities by going ALT+CTRL+DEL and going to Processes finding your games and making it a higher priority.
Also reinstalling, maybe going Vanilla in a game, if you aren't already can help.
Remember to keep your computer clean internally and externally for the best results.

Clean up old stuff
Don't download so much porn
Get more ram and a better graphics card.

All depends on what game. If it was running fine before and only started slowing down lately you might want to clear some of your hard drive, then defrag it. Google how to defrag your drive.

Next, install anti virus if you haven't got one already and scan your whole computer, you could have a virus slowing you down.

Maybe your computer isn't up to the job of running the game, post your specs and the game you are trying to play please.

You could need a new processor, more RAM or a new graphics card, as I said post the specs and game.

Thanks bros, I might try cpu clocking since I have a lap top. Is the defrag on windows 8? I'm just trying to run mmos nothing big like battle field or crisis 3.

I think I need a good free anti-virus since I think my pc been rather slow because of small viruses.

Oh! Another thing is when I go on youtube my video lags for 3 seconds after each 3-5 mins is there a way to fix this?

Much appreciate the help guys.

TTGxdemonic wrote Thanks bros, I might try cpu clocking since I have a lap top. Is the defrag on windows 8? I'm just trying to run mmos nothing big like battle field or crisis 3.

I think I need a good free anti-virus since I think my pc been rather slow because of small viruses.

Oh! Another thing is when I go on youtube my video lags for 3 seconds after each 3-5 mins is there a way to fix this?

Much appreciate the help guys.

If by CPU clocking you mean overclocking then do not do it on a laptop unless you have a fair idea of what you are doing and are confident in your cooling.

Laptops heat up really quickly and OCing your processor will shoot the heat up, if it gets too hot you could crack your motherboard and then your laptops dead.

I never did it on lap top but I have a lot of know- ledge on electronics and how they work inside since I learn a lot of about it 2 years ago. But never learn what really keeps a lap top to run fast -.- I heard having two drives one for junk and other to use for your lap top can keep it at new speed but you need to flash it. Oh thanks I did mean over clocking sometimes I forget names of things these days.

Two drives, it can help a little bit if one drive keeps all temp files stored which is essentially what you get rid off with defragging, there is multiple things to take into account with laptop speed, it will help if you post your specs for me to get a rough estimate. Things that come into account are;

Processor
RAM
Graphics card
Hard drive condition
Heat and cooling
Viruses and malware
Operating system

And many more factors, to find your specs navigate as follows (You said windows 8 right?)-

Yes window 8, will this also help my lag when I watch a video?