Computer cleaning is not an easy task. When it is overloaded with viruses, the best solution is to get out all data from there and to reinstall the operating system.
There are several tools to do this automatically. However, no tool is fully perfect to clean the computer fully. Human hands are always needed to accomplish this job fully.
First of all, if your computer is slow, then probably there are too many needless programs installed on it. To clear these programs, simply go to the uninstall menu and remove them. There is a different way on each operating system to remove programs. In Windows, we go to Start -> Settings -> Control Panel -> Add or Remove Programs. There will be a list of programs that are installed on the computer. Do not remove any program that has Microsoft mentioned in its name. These are the necessary programs Microsoft Windows needs for its operation. You will be harming your computer if you remove these programs. Also remember that removing programs could make other programs to function erratically.
If you are not sure about a particular software application on your computer, you could ask on Internet forums about what it does and whether you can safely remove it. If you are fixing it yourself in future, you won’t need any help, paid or free.
The other issue is about virus applications. These are still spread freely despite there being so many antivirus applications all around. There is actually a good free tool against viruses known as Avira Rescue Disk. You can download this as a .iso file and then burn it on a CD. Then, boot your computer through this CD and follow the onscreen instructions. The best solution here is to scan your computer with a few available antivirus programs like Avast, Avira, Norton,AVG, etc. If one program is unable to catch a virus, there are chances that another one will.
Now, if you feel that your system is slow, it may be because it cannot work flash properly on the websites. Flash usually demands more power from the processor in order to display online animation or animated advertisements. You could simply avoid it by using the Firefox web browser and installing an add-on for Firefox such as FlashBlock.
Drivers can also be an issue. The latest drivers are always available on device manufacturer websites. So, if your sound card from Realtec isn’t working well, the best fix could be to visit the Realtec website and download the latest drivers from there.