So I had some memory go bad and some other stuff go wrong with my pc about a year ago, but it was ok cause I was going to school and was using a Mac for all my school work. I just got home a couple weeks ago and I've fixed up my pc. Everything seems to work fine then I try and launch steam and it says " unable to launch an instance of steam is running on this computer under a different user" but I'm the only user on my computer.

Any help would be much appreciated

Just so your post gets a bit of a bump I'll post a couple of obvious ideas that I'm sure you've already thought of.

- Try restarting the PC

- Try reinstalling Steam.

Sorry, that's all I got, hope the bump gets your post some attention from someone with a better idea of how to fix this, Steam not working sucks.

G'luck!

CTRL+Shift+Esc to bring up Task Manager, click 'more details' if need be to expand to show all background processes, close the steam processes you find there. To be super sure, you could go to the Details tab, find a steam process, right click and select 'End Process Tree'.

Try that and see if killing off all those processes and then launching Steam again helps.

Yeah bring up task manager then go to processes tab then click the box that let's you see all users processes then see if you have a instance if steam running. Close it and you should be fine.

I believe I had a similar issue and I had to delete everything in my steam folder aside from the app data or something like that. Once I got into steam everything redownloaded automatically. I would double check on the Google machine what exactly do delete in the folder but I did not have to completely uninstall steam.