ok, last night i was going to re-install my old webcam, installed the software as planned, had to restart my computer, but when it came back on it said a few of the webcam files werent found, i wasnt particularly bothered if it was going to work or not, so skipped a couple of the files it couldn't find but thats when the problem started,

now everytime i turn on my pc it gets as far as displaying my background then i get the all-too-familiar error box:

"Cmdninst has caused an error and will now close"

after clicking close my pc just sits there not starting up, its annoying, i need to get on my computer, please help me you computer genius' from the future!

oh yeah im posting this from my really slow other pc i rarley use, incase you were wondering

See if you can get in safemode (hit f8 when booting up) and try to uninstall/reinstall the driver then.
Also make sure the cd isn't dirty or damaged. And you could see if there are newer drivers available on the net for youre cam.

RESOLVED

went into safe mode in the way you suggested and uninstalled all the programs that caused it to stop working, this didnt fix the problem, maybe i missed a program i dont know, but i did a system restore to a couple hours before i tried to put the cam on and everythings fine and dandy now.

cheers.