since this is a thread about the TV guns, i meant will the tv guns get messed up by the XP 2 player problem. i didnt think there would be any diff in that regard between the TV and monitor guns.
Like Howard said, actlabs says the TV model will add 2 players feature for all windows.
im just finishing up my cab and was wondering to go with XP or 98 cuz of that.
and is there even any other options for 2 player light guns? (i dont want a positional. dont want to mount anymore on my panel). ive never seen anything but act-labs, so i didnt think i had much of a choice 
Actlabs PC lightgun works (but not 2 player), and actlabs TV lightgun should work (and is supposed to have 2 player).
Actlabs has hinted at a new PC lightgun with the same 2 player feature as the TV lightgun some time next year, but also has stated it won't be made. Looks like the jury's still up on that one.
There's others:
The "PC virtual gun" does not work,
The actlab GS lightguns (the older gameport model) don't work,
We (many of us on BYOAC) don't see how any of the console lightguns could work, but some people have a faint hope that someone will be able to do it,
Same with real arcade guns, except with an even smaller chance of anything happening IMO,
AFAIK the jury is still out on the "
PC BIO gun". But even if the bio gun works, it will be only one player.
Finally, I think someone has removed the actlab sensors from the gun and moved them into a different gun case. I don't remember if he finally got it working or not, but IIRC there were some initial problems of some sort. You could try a search; I wasn't able to find the tread with a quick look.
So, yes, currently the only choices are actlab PC gun now, positional gun now, actlab TV gun starting in Sept (maybe later), and possiblely the "BIO gun".