Slow PC after re-install.

I re-installed my computer. It is slower than before with all stuff and viruses.

What could be the problem?

 

Try to use Disc Clean Up, Disc Defragment and Ccleaner and remove not needed stuff from your system.

If it still would be slow, then I think something is wrong with your Windows CD.

 

Update your drivers (run windows update to auto-detect the majority of them).

 

I assumed you reformatted the drives when re-installing, but I always do the long format because it checks for errors in the HD.

 

Check for errors and do a defrag if nessessary. I would also recommend installing all the critical Windows updates.

 

I did not format anything, I just put in instalation disc and installed windows. Ill try to run disc cleanup and defragmenter.

 

Have you tried updating your drivers yet? Run windows update!

 

Format your drives, and reinstall windows again if you have to.
http://www.top-windows-tutorials.com/how-to-reinstall-windows-7.html