Connected to interenet/wifi but can't connect?

[presence06]

Clients laptop:

HP Pavilion running Windows Vista Home Premium. Wasn't able to connect to the internet via Wifi, connected directly into modem and was able to connect. BUT internet explorer would keep saying it couldn't display the page and gave the diagnostics button.

Took it back to our office and hooked up to wifi and ethernet and connected but couldn't get to any websites. Ran Malwarebytes and removed 1 infected file. Attempted to run Combofix but it tells me that the OS isn't supported? Pretty sure I've run Combofix on other Windows Vista Machines and it's worked. Ran HiJackTHIS! and found a lot of @Programfiles and tried to remove them but after a rescan they came back. Booted into Safe Mode and ran HJT and tried to remove the entries again, still couldn't. Ran CCLeaner and removed all Internet Explorer/Explorer files and tried to run Rootkit Revealer (dnloaded from filehippo.com) but when I try to run it, It crashes right away.

Do you guys have any suggestions on what to try?

He has TrendMicro Internet Security for AV.