try a different output setting

They all seem to be the same. Are there any processes or drivers that are incompatible with DosBox?

Maybe try different graphics card drivers, like the newest ones or some
pretty old ones.

Do you experience this problem only with DosBox? Maybe your problem has nothing to do with Dosbox. There are issues that WinXP loses great amounts of performance with AMD dual core CPUs sometimes. A patch is available but I dont know where.

and make sure to disable/shut down all background programs. New PCs often come with a truckload of useless downlowing programs running in the back. like several Norton something programs, quicktime, realplayer, antivirus and and and...

Good news is that it is another process. Bad news, I normally have about 80 of them... Well I'll let you know what it was when I find it.

anti virus is always a good bet

Actually it was the background process to PowerDVD 6.0 (PDVDserv.exe). I'm not sure how it caused the problems, but when it's not running Dosbox works.

80 is a lot. I have 60 right now, and that's with 17 applications running.
I've had issues with that PowerDVD task eating loads of CPU time too.

I had the exact same problem (and it looks like I posted about it one day before you did), and I bet it's related to your G15 keyboard.

1) Try using dxdiag and disabling all ddraw acceleration. I bet Dosbox will come up fine. Re-enable it after for the next test.

2) Try unplugging your G15. I bet Dosbox will start up fine, and will keep working fine after you plug your keyboard back in. Everything will be pretty much OK at that point. Do you get any flickering when you start Dosbox now, but it starts up fast?

3) Reboot and see if the problem comes back. It does for me.

Hmm... so it looks like we need to get a developer a G15 keyboard. Well, more specifically, a Dosbox developer. I'm a developer, but I have a feeling Dosbox would be far beyond me right now. I might just read up on how to build the source, though.

I don't have a "fix" for this problem, besides finding some way to disable and re-enable your G15. Remote desktop into the machine works, or unplug/replugging it. Less than idea, but it's better than nothing.

Edit: Now I see that you had the powerdvd process in the background, in addition to having the G15. I do too! I'm going to disable the process and reboot and see if that takes care of it. Good catch!