Good point Josie, using IE in XP means using IE8 as the last supported version. MS isn't making the newer IE versions compatible with XP. At least that's my finding so far. Same thing with the whole .NET framework.
Newer web based applications we are developing will not run correctly on IE8. But will run correctly in Chrome/FF on the same XP machine. That machine will not run IE9 or above.
MS is up to IE11 now, so IE8 is getting left behind. Believe it or not we had a problem with a new website for a company last week that still has IE7 on many machines! The site displayed OK but admin features were not playing nicely.
They thought it was an issue to upgrade all those machines to IE8; wait until they realize all those machines will need new OS's pretty soon.
But that's an issue for the MSP guys downstairs, not my concern.

The biggest issue with XP isn't with the people actually knowledgeable about its age/lack of updates, but rather for the people that just ignore the issue and continue on as if nothing changed. (like the company above).
A newer browser can help for sure. Chrome, FF, anything but old IE versions..