Since you have Zone Alarm, I must excuse myself and ask you ask Zone Labs about that.
But if you have your OS CD handy, try IEFIX and LSPFIX that you can find with http://www.google.com to automatically correct much of the malware's damage.
In closing, since you didn't name the pest's names, I can look into what damage they do. So only generic cures can be offered.
I'm using Fastaccess Extreme from Bellsouth, and I'm having a small problem. I can connect and go to sites fine, but if I'm downloading large files from the internet, my connection will occasionally lock up. I then have to wait a couple minutes and see if it comes back, or I have to disconnect and then reconnect. The annoying part is that when the internet connection locks up, it also freezes any programs I'm running. Once I disconnect, they all run normal again.
I recently had virus problems, but all have been scanned and removed. I have all security updates for Windows XP also. I also run ZoneAlarm Pro.
I also ran tests on broadbandreports.com and it said there were no latency or congestion problems. One thing to note, is the problem really started to become noticable after I ran their tweak test, and it told me to install a program called Dr. TCP to make modifications to my connection, but I can't be 100% sure if its that, or maybe damage due to the viruses I had, or maybe something else.