PC might have malware!!!

hello,

i've been having a problem accessing a lot of websites on my browser lately.for instance when i click on some sites on my address bar or if there are any sites listed on my favourites ,when i click on them it gives me the message 'this page cannot be displayed'.there's definitely nothing wrong with my net as it seems to be connecting fine.although at first i kept blaming my ISP i realised it had to be something else blocking the sites that i visit on a regular basis.sometimes when i succeed in opening a particular website by going through a search engine,i get the message "internet security warning....the site as.casalemedia.com is trying to access the following file c:\windows\system 32\shdodc.dll ".when i googled casalemedia,i discovered its a spyware of some sort.
i went through your malware removal guide instructions.and will be attaching the logs along with this.Avg anti-spyware did not detect anything and so didnt generate any report.also i had mistakenly downloaded mgtools to my desktop first but then downloaded it again to my c: drive and ran it from there.hope that wont be a problem and hope to hear from you soon.

thanks,
veola.