I am using Google Chrome. It seems efficient at first, but I don’t think I would recommend it for old computers because it constantly builds an index of your visited web pages in the background, which can overload a small disk and slow the computer down. At least, this is what happened when I installed it on a computer with a slow disk.
To the OP: What operating system is she using? (Windows 98, Windows ME, Windows XP…)
Jakasaki and Ack are correct in that we need additional information about the computer and the operating system.
The problem is that not all browsers which work for older operating systems are easily obtainable anymore. If someone has a computer with an operating system that is no longer supported then the newest browsers probably won't work with it. I don't know if there are any Google browsers that work with Windows versions prior to XP. (I presume this is the case with some non-Windows OSes as well.)
There are browsers that can work well with some older computers/operating systems but they may not be the ones readily available.
I would have made the same suggestions you do at first but really it wouldn’t address her friend’s immediate problems. From the onset her Internet Explorer inability to update is because her registry files are corrupt. Try downloading a Free Windows/Registry Cleaner software tool here: ccleaner.com/ Also try using a good Defrag software here download.cnet.com/Auslogics-Disk-Defrag/3000-2094_4-10567503.html If it doesn’t help you might need to reformat the entire hard drive to original factory state.
I suggested the Windows/ "Registry Cleaner mostly for the Registry benefit.
As for de-fragmentation; unless you like a slow computer then what’s wrong with defrag?
Think of you computer as a file cabinet with files scatter all over hell’s creation.
Unless you want sloppy slow performance, cookies from all the sites you visit snooping at your personal files etc and corrupt broken files what’s wrong with a registry windows cleaner?
You are correct that defragmenting the hard drive will certainly speed up the computer, but it will not solve the OP’s problem (Internet Explorer’s installer not working.)
Same with the registry cleaner (which brings negligible performance improvements at best.)
In your post, you stated that your measures would address “her friend’s immediate problems” (upgrading the web browser) and I am suggesting that a different strategy would be more effective in this situation.