Internet browsers not opening or responding

Hey there. Recently on my dads computer, there have been some problems trying to open any internet browser. The only one that responds with anything is Mozilla, which flags an error, saying ''Couldn't load XPCOM". The others are completely unresponsive, not opening or giving errors of any sort.

I've tried several things - it won't let me re/uninstall anything (like the browsers, simply seeming as if I didn't even click it), tried running as admin, and the computer was even restored to a time before the error occurred, to no avail.

The last thing updated was Skype, if that helps. The update and the first time the error started appearing happened to be on the same day (Monday), so I thought that might have something to do with it. Additionally, I can still access Skype and Steam, so the internet seems to be fine. No other computers in the household have the problem.

Any insight on, or fix for the problem would be much appreciated. Thanks in advance, and if you need any additional information, go for it.

Tried it twice, again to no avail.

Bump? It's been weeks, and still no fix.

Here's something I stole from Mozilla support:

I didn't even try uninstalling/reinstalling Firefox, because seemed like it didn't work for you. But here's what DID work: I first logged into a different user account from the one I usually use (but still an administrator account). I revved up Internet Explorer (held my nose), went to the Mozilla site, downloaded Firefox (as if I didn't already have it), installed it, and kazam! Everything worked. Then (and I don't know if this was important or not), before I closed Firefox in that user account, I switched users, went to the account I usually use (and wouldn't load Firefox before), started Firefox, which went fine. Mozilla Support Thread

Go for it.

Unfortuantely, that didn't quite work out. IE still wouldn't load up - and a funny thing - firefox was still installed on the new one. (Though I couldn't uninstall it from that location.) Is there any way to make a completely fresh user, devoid of all files/programs from the original one, for further testing in this regard?

Thanks.