I'm somewhat new to LS, though not completely. I've tried to make my own themes and such. However, no matter what theme I use, the transparency effect often used in the popup menu never looks as good on my computer as it does on the previews. I'm using the latest screen card drivers and I'm sitting on a 400MHz computer... Could it be that my screen card is too old?

What kind of video card is it?
What model video card do you have?
What is your current resource usage cs available?

Ati Rage Pro 3D Turbo. Just uses the Rage Pro drivers. I have about 500 megs of RAM,and rebooting doesn' seem to help, so I doubt if resource usage is what's doing it. Could it be that I need to use Win2k or XP?

if it is using some sort of Alpha Transparency yes. otherwise start pulling all your modules out but the desktop and slowly add a module at a time until you find your problem.

Try changing your color depth to true color instead of high color if you haven't already.