Re: Some help please
Windows media player is standard with Windows so use that to play avi/mpeg files. The k-lite codec pack, links given in the sticky, will allow you to play everything. VLC will play most as well, but I prefer WMP. One is not better than the other, all down to choice.
Remove Real Player, you don't need it.
You could also do a hijackthis scan and post the log here and we can look at it and let you know what may be slowing your PC down. Info on that also in the sticky.