My three year old iMac is dying: the fans come on almost all the time, sometimes it puts itself to sleep without warning, the screen has a big blotch on the left-hand side that suffers very badly from persistent image problems and it's really slow. So I think I should buy a new one before it dies. My instinct is to go for the entry level iMac. But how much RAM should I get? And should I worry about 3.2GHz vs 3.08GHz? I mostly use it for browsing the web and doing spreadsheets. I'll need to install Windows 7 as I'm taking a course that uses a Windows application (GenStat). I download a lot of movies and often encode them from WMV to mp4. I have an iPad and encode movies to work on that. I sometimes use InDesign. I don't play games or use FinalCut. I'd be grateful for any advice. I'd like to order before the VAT goes up.