It begs question. Is the XP installed an upgrade? a full XP program? Furthermore, did you run a Windows compatability check on all of the sys hardware? XP programs on top of Vista is not the best way to go. Finally, IE7 requires XP with SP2 to work well. You could try Firefox or Opera..
I have to agree with kjanx comments, it's just going to pile up with one issue after another. Do a complete format and, install XP and all of it's updates. Check your BIOS, chipset drivers for the latest version. Stick with XP till you finis your course.
I am currently using Vista on a Toshiba laptop, P205-S6267, with 2GB of RAM. All of the latest Win updates, latest BIOS, Chipset drivers, etc. as of 1/3/2k8.
All of the programs running on this laptop...