Q: iTunes messing up my PC....

When I log onto iTunes, my PC graphics go all "Andy Worhol-like".  Also pop-ups are double letters (eg two messages overtyping each other) and I can't read them.  I've just been given an Ipad for my birthday and want to try to get this sorted.  The only way I can get my settings back to normal is to restart my PC.  I use Vista.

I'm not the most techie person, so nice easy answers please