Formatting hard drive

Hi All,

Not sure if this the correct forum for this but....

 I am having multiple problems with my Dell 4600 which started with a load of malware. That has been cleared up and my PC was running fine for about five days when all of a sudden my internet connection started running  like a blob of snot. I have optimum online which is very fast but the connection now seems to run in a loop and go nowhere. I have checked everything and cannot find the problem. I thought it might have been the router but  the Compaq on my network runs fine. I was using Netscape and IE on my Dell and they both are acting the same way. And now to top it off , out of the blue, my Macafee has been disabled and says I neeed to verify the subscription to activate it.  ....    Hmmm...problem is I can't even get on the internet now. I am tired of fixing this computer only to have something else go wrong. I can't believe it was working so well and now it just seems to have a mutitude of problems again...Every virus/spyware program I run says it's clean.  Since there is not much on this computer worth saving ,I would like to format the hardrive and just reinstall everthing. Problem is i can't even install Windows XP cause I get a msg saying it is an older version on the disk and might mess things up.On my old IBM it was very easy in DOS to format the hard drive and redo everything. I was curious if anyone can tell me how this would be accomplished on a Dell Dimension 4600.

 

Thanks

William