Gmod CTD Upon Startup

[Teh Time Rider]

So yeah, gmod crashes as soon as it finishes loading.
By startup, I mean the main menu popping up for a second.

Yeah, I've tried all of the basic fixers, reinstall, verify, etc.

Oh yeah, and it lowers my computer res in the short time that it runs.

[Sub-Zero]

Do you have the message HL2.exe has stopped working or does it just close down completely?

[De CodeerHeer]

Did you deleted the whole gmod folder? (steamapps/common/GarrysMod)

[Demonic]

Try to type -dxlevel 82 in Properties.

If that does not work just delete ur entire gmod folder like Mavis dracula said and reinstall.

[Sub-Zero]

Also before you do that try this as a last resort:

Go to your steam library and right click Garry's Mod, press Properties and go to General. Press set launch options and type the following:
-h (Height of monitor here, no brackets.)
-w (Width of monitor here. Again, no brackets.)

Eg: -h 1080 -w 1920

[Teh Time Rider]

Do you have the message HL2.exe has stopped working or does it just close down completely?

hl2.exe has stopped working, forgot to mention that

Did you deleted the whole gmod folder? (steamapps/common/GarrysMod)

Yes, twice.

Try to type -dxlevel 82 in Properties.

If that does not work just delete ur entire gmod folder like Mavis dracula said and reinstall.

Didn't work; see above

Also before you do that try this as a last resort:

Go to your steam library and right click Garry's Mod, press Properties and go to General. Press set launch options and type the following:
-h (Height of monitor here, no brackets.)
-w (Width of monitor here. Again, no brackets.)

Eg: -h 1080 -w 1920

Didn't work

[Demonic]

I also had the problem once a website helped me.

The following applications have been known to cause issues with Steam and playing games:
Anti-Virus Applications - Any Anti-Virus program could potentially block Steam and Steam game access, especially when not properly configured for use with Steam. Please make sure that Steam and all Steam games are listed as exceptions in these programs. If the issue persists, please try disabling or temporarily uninstalling the program to test the issue.
Avast!
AVG Anti-virus *
BitDefender
F-Secure
Iobit Advanced System Care *
Kaspersky Anti-virus
McAfee Anti-virus
Nod32 Anti-virus *
Norton/Symantec Anti-virus
Panda Anti-virus
Threatfire
Trend Micro
VIGuard Anti-virus
Anti-Spyware Applications
Ad Aware
CA Pest Patrol
PC Tools Spyware Doctor with AntiVirus (may need to disable Full-Screen detection in the Advanced settings)
Spybot Search & Destroy
Spycatcher Express
Spyware Doctor
Spyware Terminator
Webroot Spy Sweeper *
Firewall/Security Applications
CA Internet Security Suite
Comodo (With Portal 2 running the firewall in Defense+ in training mode allows the game to run)
CYBERsitter
ESET Smart Security
Netlimiter
McAfee Personal Firewall
Nvidia Network Access Manager/Firewall *
Nvidia ForceWare Intelligent Application Manager
Outpost Firewall (Disabling System Guard under Proactive Protection allows Portal 2 to run)
Panda Internet Security
Peer Guardian
PeerBlock
Tiny Personal Firewall
Verizon Internet Security Suite
Zone Alarm
Constant Guard by Comcast
Online Armor
Other Applications
IOBit Advance System Care
Airfoil
Alcohol 120%
AMD External Event Utility
AOLacsd.exe (AOL connection driver)
ATI Hotkey Poller
ATI Tray Tools
BitTorrent/uTorrent (all clients)
Creative Software (Alchemy, MediaSource 5 on Asus G60VX models specifcally)
Catalyst AI
Daemon Tools
Download Accelerators (all clients)
EVGA Precision
Garfield Daily Desktop Comic
GhostSurf 2007
Google Toolbar, Google Updater
GSC
Hamachi
HotSpot Shield
HydraVision
iZ3D DirectX injection
K-Lite Codec Pack
LimeWire, BearShare or other Peer 2 Peer applications
LogMeIn
Microsoft Screen Magnifier in Windows 7 (magnify.exe - may cause in-game cursor issues)
MSI Afterburner
nProtect GameGuard *
PC Time Limit
Skype
Slysoft AnyDVD
StarDock KeepSafe
SteamWatch
iolo System Mechanic
TeamSpeak (can lead to mic issues)
Total Recorder
Tuneup WinStyler Theme Service
UPEK Protector Suite
Ventrilo (can lead to mic issues)
VirtuaGirl 2
Western Digital Backup Anywhere
Whitesmoke Translator (may cause the Source engine to crash)
WindowBlinds
Xfire*
We recommend that applications listed in bold with a ( * ) symbol are fully uninstalled from your system if disabling them does not resolve the issue

Remember its not all the Programs listed just a few.

Hope this helps.