i downloaded something from limewire n now whenever i run explorer, i see two or more iexplore.exe in the taskmanager. everytime i open a new explorer, it adds an iexplore which is consuming hell lot of memory and its slowing down my computer. any solution to this would be highly appreciated.

run registry cleaner once,you will get rid of this prob

Stop using limewire altogether, if you can't, then do not download any .Zip or .Exe files. They are often spyware and F**ks your computer up. Recently I have messed up my computer and lost about 400GB of Movies, Songs, precious photos and other important documents. Better use torrent site to download programmes, software and use limewire just to donload songs. Also verify the extension before you download.

For your solution, try running msconfig, and on the "startup" and "srvices" tick only the programme that you know/trust. Untick all others.