Help!!!! All of a sudden my computer is really slow. Why is it so slow, and how can i make it run faster?

A bunch of stuff. First off, use disk cleanup if you're using windows. It'll delete unused items/programs on your computer and generally make it run a bit faster. Then use disk defragment. This is a bit more technical, but it'll also help speed your computer up. Try scanning for viruses and spyware. These will REALLY slow down your computer. If you don't have a virus protection program, try malewarebites (not the correct spelling). It's free. Or just upgrade your RAM to more Gb.

reinstall it.

maybe your computer got some virus.if so, this is what u need to do. 1)restart your computer. 2)before the computer loads the windows os , keep pressing F8 to boot into safe mode.for first timers , keep pressing F8 when the system boots up again.after pressing F8 continuously,u see a menu saying "Safe Mode,Safe Mode with Networking,Safe Mode with Command Prompt,blah blah blah".here select Safe Mode with Networking cos later on u may need to surf the web for anti-virus software (if u dont have one).if u have one,scan all the hard disks u have connected to the motherboard. 3) if the scan is over and there's nothing suspicious is found,then u might want to bring your computer to a hardware shop to upgrade some RAM which can affect the speed of your computer.if u have an old computer that u r still using (not like 10 years ago but like 5 years ago u started using?) u might want to change a few parts like the motherboard,the hard disk (before changing , make sure u create a backup.) and the RAM.peripherals like the DVD drive no need to change.cos its actually to have.its just that ppl need to use it.if u have an old graphics card u might want to sell it to the hardware shop and with some luck u might get some buck out of it. so take note.if your computer is slow,do these. 1)do a virus scan - a virus can slow down a computer alot , depending on how serious it is. 2)add some RAM (first priority) to the motherboard (u can do it yourself.its really easy.besides u dont have to pay ridiculous amount of money to bring it to the hardware shop and get that guy do it and fleece u.) 3)change to another motherboard that is suited for your CPU (im sure u dowant to waste money to get a motherboard and a new processor rite?) 4)get a new hard drive (create a backup in an external hard disk prior to getting a new one)

I must always make mention that there is a big difference between the computer running slow and the internet running slow. If Firefox opens quickly enough, but takes forever to show a page, it is a very different problem. If the problem is the computer running slowly, try pressing CTRL-ALT-DEL, depending on which version of Windows you have this will either bring up the Task Manager, or let you click on the task manager to bring it up. If you go to the performance tab, it will show you the percent of CPU you are using and how much memory you are using. If the CPU is always at 100%, there is something running in the background using all the resources, and you'll want to track down what. It could be a virus, but could also be a program that is not working properly. If the CPU stays down around 2 or 3% with nothing open, look at how much memory you are using (called PF usage below the CPU usage) vs. how much you have. If you don't know how much you have, right-click on My Computer (called "Computer" in Vista and Windows 7) then go to properties. On the general tab it will tell you how much you have. If you are using more than you have, chances are you have something or more than one thing running in the background using resources and needs to be disabled or uninstalled. If neither of those seems to be the problem, that leaves the hard drive as the third possibility of a slow computer. If its full or if its failing it will slow the computer down alot. If the internet is slow, you will need to talk to your Internet Service Provider. Sorry for the long answer, just a lot of explanation.