How do I get to my “C” drive?

To get rid of trymedia adware and some tracking cookies that keep coming up immediately after running my Yahoo anti spyware.I have a Dell 530 with Windows Vista Home Premium.I have windows defender and AVG and no matter what I try this stuff keep coming back.I am not too knowledgeable about computers so please, take it easy on me.
OK, I finally got there and still can’t find trymedia adware.It must be hiding somewhere.I tried to download free adaware but they wanted me to sign up for some other stuff so I deleted it.
I sure wish Yahoo anti spyware would just take care of this annoying stuff.

Press the “Windows”-key (next to the CTRL-key) and the “E”-key on your keyboard at the same time; the Windows Explorer opens. Click on ‘Local Drive (C)’. You are now on your C-drive, and all files and folders that are not hidden are displayed now.

Try Ad-Aware if you have problems with adware, though, it will remove it by itself: http://www.lavasoft.com/products/ad_aware_free.php