Gmod doesnt start, tried everything, help please?

well, i have prob with gmod 10. its steam version, but it wont start. i played it yesterday. and it worked just fine. but when i wanted to play it again (about hour from when i played it last time, i took my dog outside to poop) it said that i cant run 2 source games at once! i didnt have any other source game or any program besides windows open. and then i cliked ctrl+alt+delete cuz that terminates source usually. then msconfig and i found that hl2.exe was open. i terminated that too. and still nothing more than evil lookin window that sez: Error! SteamStartup() failed: SteamStartup(0xf,ox0012e84) failed with error 1: failed to take master pipe connection lock. and today steam started to update gmod 10. STILL NOTHING THAN THAT BLOODY WINDOW!!!
BTW: my computer specs are these(pretty shitty, but i can run gmod 10 with no lags, if it would work)
its laptop, fujitsu-siemens amilo li 2727, from year 2009
intel dual core processor 1.86 ghz, 2 gigs of ram
i dunno whats my gpu, but it about 1 gb.
about 43 gigs of free space on hard drive.

Restart your PC, or if you know how to use taskmgr - kill the hl2.exe process.

Failing that, delete clientregistry.blob in the Steam folder and restart Steam.

k, gonna test those, if that works, you rule.

[editline]07:49PM[/editline]

yup, im offically a dumb noob. i didnt restart the fucking computer. but thanks. its working again!