Yesterday, the computer I commonly use worked normally, but today, my computer suddenly goes slow and fragile. My browser crashed thrice just trying to load normal webpages, and it took me 10 minutes to get to this vizzed board. I restarted my computer, but it took over minute for the computer to do that, and that doesn´t work.

How do I fix and speed up my computer?

Sounds like somebody's proooooobably got malware if your computer slowed down that much within a day.

First and foremost, have you run any virus scans?

Minuano : Yes, I´ve scanned my computer for viruses. I used Avast, and it only says that some programs are out of date or have a bad reputation. It doesn´t say anything about malware.

Right click your task bar and go to your task manager. Are there and programs that use a lot of your cpu, memory, disk, or network?

I actually had a similar problem with my computer as well.

Like earthwarrior suggested, I went in to the Task Manager and checked which program was causing it. It was a program labeled svchost.exe under the User "SYSTEM," so I wasn't exactly comfortable just ending the process ( since that can wreck the computer if done to the wrong thing ). You can Right Click which ever program is using up the CPU, and click "Go To Services." It will then highlight exactly which programs under the Services tab that are causing the issue. You can also try out the "Open File Location" or "Properties" options to figure out more about where the file is located and exactly what kind of program you're dealing with.

For me it ended up being Windows Update causing the problem. It would use about 1.5 - 2 Gigs of RAM and at least 50% of my CPU just to idle and accomplish nothing. I had to go to the Services option in the Control Panel and completely disable it altogether. I can't say your issue will be the same thing, but hopefully this provides a little insight on possibly how to fix what's causing the problem.

If you do have malware but no antimalware I suggest downloading a trial of Malwarebytes, it's probably the best free one I can think of off the top of my head.

It fixed our computers up a little when MY FREAKIN DAD got some things into it. Thanks, dad.

yoshirulez! : I've downloaded Malwarebytes a few days ago, but the computer is still extremely slow. At one point, the whole system crashed when I was trying to delete a game off my computer.

Maybe your hard drive is starting to give up? Or much worse the motherboard? Or it can also be simply due to overheating.