Connected to Internet, but cannot ping ANYTHING

Question

One of my company's customers has an issue with their windows 7 machine that I have been trying to help him solve to no avail.
The problem began when he was suddenly unable to use certain functionality of our software several days ago- having changed nothing that he was aware of on his computer. Though his computer is connected to the internet, and he can browse the web, send email,
etc, he is unable to connect to our SQL server, and though he is able to connect to our FTP server, he is unable to upload or download files from it.
To begin diagnosing the problem, I had him perform a ping test. First to our SQL server, which failed, then to our ftp server, also failed, then to google.com, which failed, then to his router, which also failed. Of all the ping tests performed, the ONLY
one that gets a response is when he pings localhost or 127.0.0.1. The nature of the ping failure is four: "The Request Timed Out" messages.
I logged into his router and was able to successfully perform all ping tests through the router ping tool. I had him log into another computer on his network, and all ping tests worked from that computer. 
He had the following software installed: Windows Firewall, SpyBot, cCleaner, Windows Security Essentials, MalwareBytes and AVG toolbar. I uninstalled all of these except for Windows Security Essentials, disabled the windows firewall and rebooted, but the
problem remains.
Rebooting in "safe mode with networking" had different results. Instead of the timeout error he just gets "Ping request could not find host... please check the name and try again".
He does not have a proxy or any other complicated network setup.
His HOSTS file is in the default state, however there are a number of renamed HOSTS files in the same directory, one of which appears to have been generated by SpyBot, and has hundreds of entries, but it is renamed to HOSTS.OLD.
My hunch is that some software on his computer did something to block certain types of network communication, including ping and that uninstalling that software did not revert those settings, but of course I can't be sure of that.
Any ideas on what could be causing this issue, and/or how to resolve it?

Answer 1

1. I have the same experience with SpyBot. It creates hosts file entries and make the response much slower.
2. To have so many AV programs on single computer is counterproductive.
3. I would avoid using cCleaner based on my bad experience.
4. With ping you can test the connectivity and connectivity with name resolution. The necessary condition is that the path and target computers allow for ping. (FW allows for it.). Use nslookup to check the DNS.
5. Use network monitor to resolve your problem. Without more detailed information on packets flowing in your network it is not possible to find the cause of troubles. Wireshark will do the job. If you feel like not to analyze logs from network monitor, upload
log file and share URL.
6. Appropriate ports should be opened. Scarce information is given on SQL and FTP connection. (These ports belong to notorious attacked ones. )
Regards
Milos