Is this your webcam? http://www.trust.com/products/productsupport.aspx?artnr=14382
I downloaded the manual and it looks pretty straightforward to me. Try the troubleshooting steps at the foot of that link if you can't get it to work.
Also, in WLM, press ALT to get the text links, go to Tools, Options and in the first menu called "Personal", make sure that "Allow others to see I have a webcam
" is checkmarked. Run the "Audio and video setup" menu (in Tools menu) too.