Getting "Application Error" while playing CounterStrike

My computer is pretty much new... all new parts, built recently..

Up until today, I've had no problems with CS or the computer at all..

Now, I keep getting this error while playing CS... I'll freeze, then error pops up and I crash.

it says..

The instruction at "0x0ebb5969" referenced memory at "0x0ee45700". The memory could not be read".

Click on OK to terminate the program.


Also, my computer has been randomly rebooting all day....

Any ideas? Thanks.