Open Task Manager and go to the Processes tab, Check if there's a Steam.exe listed there. If there is one end it then try launching Steam again.
will it affect any of my games?
Try going to the folder where you installed Steam and renaming/deleting ClientRegistry.blob. Then launch it again.
A magical thing that requires an IQ above sixty to understand!
Hey! i resemble that.
Delete everything in the Steam folder except Steam.exe and steamapps.
will that affect anything
Not really, no.
[size=1000pt]WTF IS STEAM?!?!?!?[/size]