I'll guess that you have integrated video cards on both machines which are underpowerd... If that's the case, then you need a better video card with a good amount of RAM.. In addition, running the XP operating system with a bare minimum just doesn't cut it.. A bare minimum for a decent running XP is 512 MB and in your case, you've got less than that.. 1 GB would be better and you might try doing so.. After upgrading the RAM, access the BIOS settings and see if you can increase the amount of RAM allocated to the video card.. Some BIOS settings give you such an option.. Some don't.

So up the RAM to 1 GB or more and if you could, install a separate video card with 256 MB or more and it should work better. Unfortunately, laptops usually don't have an upgrade for their video cards and you'll have to live with just added system RAM..

Remember also that the Sempron and Celeron processors you've listed aren't barn-burners either..

Basically, when the video needs more "uumph", the two computers you've listed just don't have it.

Hope this helps.