Can connect with some programs, but not all.

Hello,

Recently I received an old computer back from a computer store where the hard drive was replaced. This computer is XP and is not Vista. I connected my computer directly to a modem and upon boot, I was surprised to notice that they had been able to transfer my computer's stored files over so that essentially all installed programs and the such were still there. At that time, I launched MSN Messenger and it worked perfectly, I also brought up Mozilla Firefox 2.0 (an outdated version) and it connected to the internet just fine. However Internet Explorer, PlayOnline Viewer (MMO Program), and Skype (to name a few) would not connect. In the time that I was trying to figure out was was wrong I updated Firefox on that computer to the latest version and upon completing the update, Firefox would then no longer connect to the internet.

This has left me, frankly, quite frustrated as I cannot find out what's causing these problems. I've searched other forums and read responses considering Firewalls and Zone Alarm. I've disabled the Firewall that was initially active and there was no change to my problem. Concerning Zone Alarm, I've checked my programs listing, and even did a search for 'Zone Alarm' through the search function and have yielded zero results for such a program being installed; however when I check the Process listing through Ctrl+Alt+Delete there's a program listed as "VSMON.exe" eating up a lot of processing power and VSMON.exe is a known function of Zone Alarm, which I cannot find.

Does any one have any ideas or advice that might help? :(