hello guys yesterday i made a mistake did not realize that my new PC had different ram slot(DDR3) i tried to ADD the Ram memory from older (DDR) PC(witch fitted only half off it than i realized that it was not okay) and now when i try to start my PC it keeps on beeping 13 times and than restarts bought new RAM but still not working .
Any Ideas how to fix it ?

Thanks Remove ALL RAM and do 3 4 cold boots and shutdowns...

Then replace the PROPER RAM.Hi

If what Patio suggested doesn't fix the problem .

With the DDR memory installed did you try to TURN the computer on? if you did it is likely you have damaged the motherboard. Or that the DDR memory physically damaged the memory sockets.
 Patio thank you for the idea i tried it did not work it is still beeping and wont start .
VintronNZ yep i started it ,  may be one of these problem :/ .
thank you for your TIME guys and in the unlikely event of dust and lose components, try REMOVING, cleaning and reseating the video card if the PC has an add-on one.
if not, I'm with Vintron - you have pushed that incompatible memory in too hard and screwed up the slots.