Can't start TF2

[Spark]

No matter what I do, when I try to start TF2, I am faced with the message "Only one instance of the game can be running at one time.". I've so far tried:

• Verifying the game cache integrity
  
• Appending -safe and -autoconfig to the launch arguments
  
• Killing hl2.exe, even though there isn't one(taskkill /f /im hl2.exe does nothing)
  
• Restarting Steam
  
• Restarting my PC

without any luck.

I'm not entirely sure, but I just recently updated my GPU drivers and I can remember TF2 working only once after the update. It never worked since then.

What can I do other than reinstalling the game?

[Spark]

bump

[Tev]

Try disabling background programs with selective startup and see if the issue persists.

Hold down the Windows and the R -buttons
Type in msconfig
Click the Selective Startup -option.
Untick Load Startup Items

Select the Services -tab; tick this:
Hide All Microsoft Services

Press
Disable All

Apply & Close
Restart PC

If it works, add the programs back in batches to narrow down the program(s) that cause(s) this issue.

[Alfrink]

If you have the bandwith to do that, I think a clean reinstall would be the best idea. I don't know what else you could do. Since your inventory and everything is server-based, you won't lose anything.

[Spark]

I got it... I disabled Tweaks > CrossfireX Tweaks > Show MVPU mode OSD in RadeonPro and now it works properly. Thanks everyone for the help anyway.