there could be any number of thing(s) that are going wrong or have already gone wrong.  What any service technician will do once they have the tv is watch the flashes for a pattern.  9 times out of 10, a noticable pattern can be seen by watching the flashes.  It is the tv's way of saying what is wrong.

Now this is only an example, and is by NO MEANS what the flashes mean... but if there is a pattern, it could be like this...

2 flashes, power supply

3 flashes, display error

4 flashes, etc etc etc...

a fast an easy way is look up online the model and error codes.  there just might be an answer waiting for you.  This may also save you money, if the unit is no longer under warranty, by saving the tech some billable time/hours.  The tech will do the same thing as you do to determine the issue.

good luck and may it be a cheap fix...