Why has my computer became so slow!?

So yeah, I used to play WoW on this computer quite often, as my laptop which I usually played it on broke as the E key and the T key stopped working (had that laptop for a year, spent alot of money on upgrades such as RAM now I have to use a keyboard whenever I go on it because can't repair it).
Anyway, my desktop used to run all smooth, I could have multiple things up at a time, including youtube, WoW, iTunes and a few other internet tabs.
However now, when I have just Sythe, Epicbot and Skype open my mouse goes REALLY slow, slow as in, it will lag so bad, then jump, so pressing small icons is really hard at some points! I've checked everything, even for viruses. I don't play WoW anymore and removed that from my computer, I still have Diablo III installed however.
Things are just getting really annoying now, so annoying I want to switch to my Laptop but that gets annoying using a keyboard, I only really use that for RS when i'm watching TV aswell. I try and PK on RS and often, i can't have ANYTHING else open otherwise my whole computer will lag for a few seconds.
My computer is pretty old, probably about 10 years old, I also have a custom built one but that's even older and has mostly been salvaged for parts.
I don't really know whats in my computer anymore, it has standard issue ram, so like 2GB and also a awesome graphics card, GeForce GTX 460. I've tried swapping graphics cards but with no luck..
Anyone got anyway I can speed things up or is something really wrong?

Thanks

 

A reinstall is probably the best, you just have to reinstall your programs and back your data up. Best is just to back all data up to your D drive and reinstall windows on C:\ and don't format D:\ Make sure to format C:\ before installing windows, you can do this in the installation process.

There are alot of other things you can do but they're not really effective and in total it will probably add up to the same time it costs as reinstalling windows. And reinstalling windows will always be superior over these methods.

I already noticed my computer got a bit slower after having it just for 1,5 years so I simply reinstalled it this week, was done in 2 hours with reinstalling windows and programs etc.

Things you can try without reinstalling though are:

- Defragmentation
- Ccleaner (cleans up temp files and IE & Firefox temp files)
- Malwarebytes (virus, spyware, other malware)
- Msconfig (disable certain programs or services from starting up
- You could consider slightly overclocking your CPU and possibly Memory (warranty will become void however if you only overclock a bit I can almost guarantee you nothing will happen)

 

Tried pretty much all of the suggested, going to reinstall and see how it goes.
I start my new job soon and I think considering the computer is really old, it's time for a new one. Going to try and build it myself

 

Building yourself is indeed the best option to save money and get the best performance. Alot of people think it's too difficult but it's really not and definitely worth it so good luck.

 

Yeah, got to say I agree with Just un dude here 100%, I recently had some money to purchase a desktop computer and I looked around for ages comparing computer parts to prices of pre-built computers and literally couldn't believe the difference in price.

I have no experience at all of building computers except what is available on google, I purchased all the parts and built it in less than a few hours with no problems at all. I'd encourage anyone who is slightly interested in it to give it a try.

 

Back up your data to D drive if you have one or use an external drive or USB stick for example or a CD.

Get your windows CD and CD Key ready.
Insert CD and start up, press any enter key to boot up from CD (it will say this on screen).

During installation don't forget to format C drive and install windows on there after formatting it. More detailed guides can be found... everywhere on the internet.

 

you can always make ur laptop go to factory mode,just as u bought it, it fixed all on my pc, games run wayy better now. also most likely windows update slows ur computer with new updates,some maybe not instaleld correctly and so on.

you can google factory setting on google,easy and fast.