No Internet Connection after a Virus Removal

Hello,

I recently discovered viruses on my Dell Inspiron N5010, on two different occasions.  The first two viruses were taken care of, but McAfee virus scan always stopped working when 75% done.  So, I kept scanning multiple times every day.  Within a couple of days, I found another virus, and got rid of it, too.  Then, when I restarted the computer, I had no internet connection. 

My computer is connected to the network , but not to the Internet.  All other computers and iPods at home are connected to the internet on the same wireless network, and they are working as usual.

My OS is Windows 7, and my computer uses DW1501 Wireless-N WLAN Half-Mini Card.

I tried all kinds of things recommended on the Internet to restore my connection, with no success.  I tried system restore, but all the restore points before this problem were deleted.  (by viruses?)  I contacted McAfee, but none of their suggestions worked to restore the connection.

Everything else on my computer seems to be working although McAfee virus scan (full scan) now takes a whole day to finish.  (It finds no viruses.)  I set my computer never to sleep, but it sleeps anyway.  I even tried my system backup disc, hoping to restore the factory setting, but the disc always receives an error message, and never did a single thing for me.  I made another copy of system backup, which ended up with the same results.

Could anyone help me with this issue?  I wouldn't mind resetting my computer to its original state if it resolves the problem, but I just don't know how to make my system backup disc work.

Thank you,

Akiko