Did you try rebooting again?
Also try running the Virtual Technician: http://mvt.mcafee.com/ it can often fix things.
We would need some more information to offer any other suggestion, other than contact Technical Support which is free and linked under Useful Links at the top of this page.
What operating system and service pack is this is it totally up to date?
What version of McAfee is installed?
Rebooted a four times, and the message McAfee Service Host has encountered a problem and must close is still appearing.
However Chrome is unblocked on the latest reboot.
I will try running the Virtual technician.
XP SP3, all up to date. Virus Scan 15.0.302, SecurityCenter 10.5.195
Sorry, open SecurityCenter by double-clicking the taskbar icon and then click About and post the version for SecurityCenter.
It might do the trick but I know this involves time and patience.
Uninstall everything, then run the MCPR cleanup tool listed under Useful Links at the top of this page and reboot.
Reinstall from your online account.
Failing that I think your best bet is to open a case with Technical Support, also linked under Useful Links.
It's free by phone or online chat.
That sounds too technical for me, so I'll mail support :-(
Mail? That would take forever. The phone is the best bet and online chat the second.
Try the MVT first as I suggested.