If you have trouble with downloading the tools you need, try to download the installation programs on another computer and save them to a flash drive. Boot the infected pc in Safe Mode with Networking (Press F8 multiple times on bootup before the Windows Logo appears to bring up a boot options menu). Plug in the flash drive, install, update, & run Malwarebytes, spybot s&d, & Hijackthis. Save & Post the logs for each of the cleaning programs you use. If your web browser is badly infected with BHO's &/or activeX applications, you may need to save the logs back to the flash drive and post them from a clean computer.
Hope that helps.
Zyldar