How do I get rid of some corrupt adware?

Please help! I have tried almost everything… I can’t access comcast’s free Mcafee service, of Lavasoft’s service, or anything that has to do with virus removal or “ware” removal… because the thing on my computer doesn’t allow the browsers to access those sites (probably due to a line of code). We are not willing to pay hundreds of dollars for antivirus, so we are considering replacing the hard drive (on warranty.). Is there anything else we can do before our last resort?

Some details:
When browsing, on Google, if I am to click on a website, it will redirect to a ad redirectory site (you know, the kind when you mistype a web address and it comes up with some illegal domains).
I get FULL-WINDOW popups, which my popup blocker doesn’t block.
My computer is going slow.
And registry editing is blocked.

I have a bunch of list 4 you to download n install it

► Windows Malware Removal: http://www.microsoft.com/downloads/details.aspx?familyid=ad724ae0-e72d-4f54-9ab3-75b8eb148356&displaylang=en
► Windows Defender: http://www.microsoft.com/downloads/details.aspx?FamilyID=435bfce7-da2b-4a6a-afa4-f7f14e605a0d&DisplayLang=en
► SuperAntiSpyware http://www.download.com/SUPERAntiSpyware-Free-Edition/3000-8022_4-10523889.html
► SpyBot – S&D http://www.download.com/Spybot-Search-Destroy/3000-8022_4-10122137.html?tag=mncol;pop&cdlPid=10861988
► Malwarebytes Anti Malware http://www.lancelhoff.com/2008/12/05/how-to-remove-perfect-defender-2009/
► AVG Anti-Virus Free Edition 8.0.173: http://www.download.com/AVG-Anti-Virus-Free-Edition/3000-2239_4-10320142.html?tag=mncol&cdlPid=10891365
► Registry Cleaner http://rapidshare.com/files/167043392/CCleaner_setup_v213-ges007.zip

Clean-up your PC, and don’t forget to clean up in save mode, most of pop-up can not run in save mode..

these portable removal tools also can removed pop-up
► Portable AntiVir Avira Removal Tool: http://directdownloadcenter.com/avira-antivir-removal-tool-for-windows.html
► Portable Mc Afee Stinger: http://vil.nai.com/vil/stinger/default.aspx

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Is your anti-virus working properly?