ASCTray.exe system error program can't start because rtl120.bpl is missing

I want to thank whomever offered these productive suggestions. First, I have Windows Home premium 32/64, with Kaspersky Antivirus 2011.  What happened was,  I upgraded FireFox5 to the FF6 beta, thinking it wasn't beta, and it stopped Netflix streaming on FF6, Chrome and IE8.. I went on the web to find answers and decided to uninstall the v.6 and reinstalled FF5. I then uninstalled the Silverlight 4, reinstalled V.3, following a web suggestion. Netflix remained jammed. Not quite sure when the ASCTray.exe error message appeared. I uninstalled several other utility programs as ballast and called the folks at Santa Rosa Computers, who put together my modest set, and was told to search around some more and be careful of clicking fishy links.  I called NetFlix, and a charming woman walked me through a short procedure that got my Netflix back . Some where in all this, that error message disappeared. I didn't have to use this good help. I am, nevertheless, grateful to those who helped me. Kindness is the Best thing that we humans can offer each other. What the woman at Netflix offered was this: Start>Run>%programdata%>Enter. On the page that appears, click Microsoft. What shows is: mspr.bdds. Delete that. That is when the Netflix streaming was restored. Don't know if that will work for everyone else, but it did for me. She said that Silverlight "left things laying around". I also used the Silverlight  v.4 plug-in for FF5 and it works fine. It's all still a mystery to me.  Thanks to all. Ratguard.

       I am sorry, my above comment omitted a step in recovering the Netflix. It goes: Start>run>%programdata%>microsoft>playready> then the page containing: mspr.bdds>delete. That's what she said. Ratguard.