explorer.exe generating error, please help!

hello and thanks in advance for any help!

heres what happened- i wanted to play a new game on my pc and was told that i needed to update my video drivers in order to do so. i have an ati radeon all-in-wonder 7500 video card, so i went to their website and downloaded a bundle which included the new drivers. after installing the new driver package, i noticed that i could no longer access the internet.

i went to the command prompt and ran ipconfig /all. apparently all of the ip info had been wiped out. the pc did not have any ip address, not even an apipa address. so the logical next step was to go into my network connection settings and reconfigure the tcp/ip settings to enable dhcp and get an address from my router. heres where the problem happens.

every time i try to open the properties on my network connection, a window pops up telling me that "explorer.exe has generated errors and will be closed by windows- you will need to restart the program.". this leaves me with no way of fixing the network settings to get back online. very annoying.

so i've already tried a few things to fix this to no avail. i tried logging on as another admin and still the same problem. i tried going back to the old video drivers but no luck. i tried re-installing the network card drivers but no luck. i ran norton av and ad-aware but no luck. i tried running sfc /scannow and still no luck.

i noticed 2 things that might be relevant in my services window. the microsoft windows service could not start because the system.exe file was missing from the c:\winnt folder. however i found it in another folder and copied it to the winnt folder and when i tried to start the service i now got an "error 5: access is denied" error. the same thing happened with the windows kernel service, except in that case it was the svchost.exe file that was originally missing. i dont even know if this is even relevant, but i'm trying to give thorough info for whoever can help.

can anybody help me fix this, please?