Hi there, finally joined these forums after years of viewing and restraining from making silly comments. I've been a Mac user for about 4 years and have only just encountered this problem since i've been back from uni for Easter (on my parents' Mac too ). The problem occurs when I hover my mouse over things e.g. drop-down menus, apps in the dock, links on webpages etc. I'm not getting the usual highlighting or bold/underlining on links, nor are the titles of apps showing on the dock when I hover. Furthermore a central mouse click brings up scrolling arrows but moving the mouse both up and down doesn't work . It's all rather perplexing, a reboot seems to fix the problem temporarily but it soon returns (when exactly I'm not sure as I'm not the primary user and my dad's unlikely to notice but I know something's up). They've got a 1.83GHz Intel Core 2 Duo Mac Mini running OS 10.4.11, I think it was from about 2 refreshes ago but I can't remember. Sorry for an exceedingly long post but I thought detail might help, It's good to finally be a part of these forums.