xp system browsers fail after a few minutes

why don't you save the data to an external hard disk and reinstall a clean system?
The more cleanup tools you use, the danger rises that they destroy the integrity the system.

Keep also in mind that xp is just another year supported with security updates by microsoft.

Hi fmarshall,
I definitely agree with Tolomir above it's always better to format and do a clean install as that will resolve everything and last a lot longer, and security updates & damaging the integrity of the system is a big one - that is the best solution if possible. It may be worth it if you wanted to upgrade to a newer version of windows, Windows 8 you can upgrade to for pretty cheap if you wanted and is fairly easy to install.

If that is not a viable option in your case you can try resetting the user profiles for the browser, see below for links with instructions for Chrome and IE and just post back if you have any issues or questions!

Chrome: http://evansims.com/6425/resetting-your-chrome-user-profile/

For IE see: http://www.ghacks.net/2010/08/02/reset-web-browsers-to-factory-default-settings/
*I would suggest only use the instructions on this page relating to IE - for Chrome/etc it's always better to reset the profile by deleting them manually wen available. Good luck!

just to add, if you move now to windows 8 you get Windows 8 Pro upgrade (from xp) for $39.99 ERP (regularly priced $199.99 ERP) offer valid before Jan 31, 2013.

http://windows.microsoft.com/en-US/windows/buy?ocid=GA8_O_WOL_Hero_ShopHP_FPP_Null

If you want you classic shell try this: http://www.classicshell.net/

put the XP disk in cd rom
go to run and tyep
 sfc /scannow
run it...

all the best
it'll replace currupted system files

Windows 8 links Tolomir posted is a great deal but won't be available for long so definitely worth looking into into! And sfc command works great but if its affecting chrome and IE the problem isn't isolated to windows file as that fixes, if those are your only problem definitely do the browser profile resets as that should fix it since they were working fine in safe mode so will clear whatever was causing that but also may be worth running sfc to nab any windows issues, take care!

... for long, no only 3 days left ;-)

@Tolomir,
Haha that's why I said NOT for long ;) But even I wasn't paying attention to where it was only 3 days ha, definitely worth nabbing that while it's still available as they already stopped it for Windows 7 upgrades and it really is a good system contrary to some of the press - you still have your normal desktop which is near exact as prior and there are a lot of good new things albeit different :)

Don't tell me I've got my 2 licenses + free media center.
I don't like the metro design though (running them in vmware workstation anyway)  
With start8 usable.

While I do appreciate the suggestions that are outside the scope of the question, I did ask the question the way I did purposefully.

Reinstalling Windows is always a fallback but my main objective is to fix the thing so that data and installs remain as intact as possible.  There are situations where this has value.  So that also lets out Windows 8 if one really wants to deal with it - I'm OK with it but many do not.  But, we digress.
(There are also situations where a new install should be the FIRST thing one does because it's cheaper/better).

I tried to suggest that I have plenty of experience doing this kind of thing.

I'm not having the usual good results

So, I've already used:
sfc
Malwarebytes
and *many* other really good tools of that sort.
Not Roguekiller though... I'll try it.

I'm more interested in what this could be and how to mount a focused attack.  I've never seen anything quite like this before:
- the browsers work ... and then, after a time or after being in use, don't in Normal mode.
- I beleive they work in Safe Mode.
- there were signs of browser hijack as URL were turned into legit IP addresses (automagically)  but still didn't work.
- because of the delay, it's hard to wade through msconfig startup and trim things and and then test .. because the test takes a while.  But I may resort to that.
Big question: what can it be and/or where to find it or a focused tool to fix it?

Also, I don't get the feel that this is a broken OS as compared to an infected OS.  Time will tell on the former.

Instead of using msconfig. Use autoruns from sysinternals/microsoft.

It will show you a lot more results.

tx for the feedback
a new profile is clean - unless you copy the old contents to it

Thanks for the help!
Another success in preserving User's computer!