New virus? Or something.

Like I was outta town last night and then when I got home it seems my brother got a new virus on the comp. Like it has a windows update notification blinking all the time going "your computr is infected!" "dangerous maleware infection was detected on your PC, blah blah blah" It also changed my home page to make me try and download Malware Wipe or Spy Sherrif. I tried using virus scans and so on but it doesent work. Please help

Those "your computer is infected" notifications are there to trick you into downloading their spyware-infested software, often trying to bilk you out of money to register them. Doing anything they prompt you to do will only make the problem worse. You need a proper adware/spyware removal tool. Microsoft Antispyware, Spybot Search & Destroy and AdAware are the obvious suspects, though I've encountered the Spy Sheriff range before and found them a right pain in the ass to remove (hint: disconnect from the internet after you've made sure your spyware software is up-to-date, but before you start the scanning and removal - it's a bastard for reinstalling itself).

Formatting never hurts. Seriously. Just make sure you saved all you really need.

If you're feeling up to it, manual removal instructions for Spy Sheriff are here:

http://www.delphifaq.com/faq/windows_user/f850.shtml

what if it hasnt changed my back ground though is it the same problem still?

I once ran into something that had no name.  It made new processes with random names, browser hijacked to sites like Starware, and was unremovable by every legit spyware/adware remover I could find.  

High chance your comp got caught by the new WMF-vulnerability. See here: http://www.microsoft.com/technet/security/advisory/912840.mspx
Basically this means, you cannot safely view image files of any type from the net on Windows. Micro$hit hasn't released a patch yet.
Problem is, there are so many variations of this in the meantime (50+) that no AV-tool can safely remove all of them. Format and reinstall. 

>>7
Don't be an idiot. There are many mechanisms by which malware can get onto a computer, all of which can lead to you being infested by Spy Sheriff and similar con-trick "helpful" tools. It could have got in by any number of other known security holes, ones far more widespread and therefore more likely than one that was discovered just a few days ago. My brother's computer got nailed by a very similar conware program several months ago (long before the WMF vulnerability was known), and the symptoms were the same. Besides, the method of infection is irrelevant: it doesn't matter if it got in by ActiveX, an infected e-mail attachment or some buffer overrun. Removing the infection comes down to the same thing (and in this case it's a tough bastard to remove, so I'm inclined to agree with the reinstall suggestion).