Unfortunately, no, you can’t bypass a virus that is blocking your Internet access via a proxy, when your computer is boot up normally. Certain malware variants have the ability to modify your Internet browser settings by adding their own malicious proxy server, changing your computer’s DNS settings, and even adding entries to your operating system’s Hosts files. When that happens, you may encounter redirect issues or having your Internet connection completely blocked. That’s why you will not be able to visit any websites to download the required software to eliminate the security infections – no matter what URL you type in the address bar.
How to Troubleshoot
As you already know, there are malicious processes that are presently running and preventing you from using the Internet. You must kill them or else they will keep reproducing the files forever. First, you can try booting up your computer in safemode with networking. In most cases, you should be able to access the Internet. Try to download an appropriate that can kill all the processes that are associated with the virus. Download it, run it, and wait until the program has done its job. You need to note that some viruses will try to warn you that the antivirus program that is being run is an infection. If that happens, ignore it.
Even after all the steps above are completed, you should not reboot your computer yet. You need to make sure you cover all follow-up steps, including a full scan, outwitting the virus by renaming certain files etc.
Reminder: It is important that your computers are protected by reliable and up-to-date antivirus programs. Whether you use a proxy or not, it is essential that you avoid visiting malicious websites, downloading software you don’t need, opening attachments from unknown senders, and more.