Emu XL-7 & MP-7 User's Group

Hi, Can anybody give me some useful advice on how to attempt to 
restart my Xl. When I switch it on the main display lights up but 
there is no Xl7 logo scrolling across the screen, its just blank
with a single cursor that won`t move. Non of the other lights come on 
either.
Also if I cannot reboot it myself, could somone tell me where I could 
find a reputable Emu repairer in the UK.
Many thanks for reading, please help . You know how devastated you 
would be.