Gmod Crash

So I go onto steam and launch gmod after loading it pauses because their are addons to be downloaded while they are being downloaded after a while gmod crashes and along with it crashes steam too please can someone help me.

If Steam crashes as well, the problem is beyond GMod.

It says SteamPipe is not responding.

SteamPipe, what?

nvm it is not steampipe anymore It only crashes because of lua error something went horribly wrong not enough memory can you help

[editline]7th August 2015[/editline]

That only happens when it is sending client info

Add -heapsize 524288 to your startup parameters

Where is the startup parameters.

ok thanks.