I have Aspire 5750 which boots up into Windows 7 64bit but in the main colour of red.

I thought the problem was with the screen as when I attached external monitor the monitor showed windows etc all normally. I changed the screen and then replaced battery and restarted but it still boots up in the main colour of red, have tried re-calibration of colour but this does not correct this issue. Laptop has Intel I5 processor and 8gb of ram and cpu is running cool. Can anyone provide me an answer to this frustrating problem which I thought was the VGA but maybe it could be with the LED cabling which is my next focus!! Open to any solutions from the community , thanks in advance!! Geoff