Issues with opening programs

Okay i recently downloaded these two programs

SafeXP
GameXP

More info about thesehere

Basicly these programs are supposed to speed up Windows but what it basicly does is removes loads of usefull things which windows does like file association etc. at the gain of just a tiny bit more speed.

Okay so I didn't realise this at first , so of course when i realised that these two programs cause more harm then good i removed them. Everything was fine until i realised that when i clicked a song or a picture nothing happened i even right clicked the file and clicked "Open With" . Still nothing .... Happeneds. So i tried to open Windows Media player and even Windows Picture and Fax viewer . And still! nothing happeneds. Okay so i decided to reinstall windows media player and still nothing has happened and it still goes blank when i try to open something with it.

I don't know much about computers but im guessing this program removed file association and altered some .dll's or something......I have tried system restore but i cannot get back to the date when i installed these two programs unfortunatley.

If somebody could shine any light on these issues it would be great thanks!