I'm not much good with bike mechanics, but that doesn't stop me trying. After replacing my derailleur, chain and sawing off my chain guide I discovered that it was a worn cassette that was making my chain skip. I ordered a 9 speed LX cassette to replace whatever was on before (Acera I think). However, having just attempted to remove it I realise it is not as easy as I thought. I have a screwdriver with a bizarrely shaped handle that will fit into that star shaped thing on the smallest cog of the cassette but (if that will do the job) I am not sure how to unscrew it or whatever. If someone could give me some advice it would be useful, bearing in mind that my LBS is by no means local. Also, I've been reading about Uniglide and Hyperglide, will this affect the chances of my cassette fitting to my hub, which is a 98 Acera?