help me with some problems!

I have two persistant computer problems that I just can’t figure out. FYI: I have Windows XP with all updates, an AGP NVIDIA GeForce 6200 256mb video card, a gig of ram, and an AMD Athlon XP running at 1.29 GHz.

• I installed a new video card (the aforementioned GeForce) when my old one exploded. Everything’s super, except that about 30% of the time after I reboot, the bottom of the screen (about two millimeters of it) is cut off and imperfectly reproduced at the top of my screen. When this happens, the “LCD adjust” option on my monitor’s on screen menu is greyed-out and there’s nothing I can do to fix it except reboot. Rebooting fixes the problem about 70% of the time, but it’s not a panacea.

  For what it’s worth, I tried reinstalling video card drivers as well as reinstalling the video card’s control software–to no avail. If you have any insight on either of these problems, please let me know.

• I’m suffering from some strange USB problems. I’ve had a lot of trouble getting my iPod to connect to my computer–almost every time I plug it in, I get an error message saying, “One of the USB devices attached to this computer has malfunctioned, and Windows does not recognize it.” I tried reinstalling the iPod software and reinstalling iTunes, but nothing really fixed the problem.

  So that’s annoying, but here’s where it gets really annoying: sometimes, when I plug in OR unplug a USB device (including but definitely not limited to iPods), the computer spontaneously reboots. This doesn’t exactly inspire confidence.

  Anyway, I tried uninstalling all USB controllers/hubs in Device Manager and having XP detect the hardware and reinstall it, and it didn’t do anything (except force yet another sudden reboot–I’m feeling lucky that the USB hardware managed to reinstall itself at all).

What do you think, guys? Am I totally screwed? Do I have a VIRUS??$#@!?$ (VirusScan hasn’t found anything naughty.) Is there a logical next step for either of these problems?