I installed OW a few weeks ago, played it just fine, then shelved it. When I went back to play it again after a few weeks, it just wouldn't run. I would double click the icon and nothing would happen, I wouldn't even see a blip on the list of processes running. I also was receiving virus warnings from AVG about freshly downloaded OW files but figured I'd just ignore those.
I have installed the latest patch (10b), and reinstalled the entire game to no avail. The game still will not run. I also noticed something odd in the compatibility tab of the owar.exe, it's permanently set to Windows 98/ME compatibility and it reverts back to that option whenever I make a change. Is that intentional? I wanted to try out other compatibility modes but it looks like I can't.
Please advise :)

Odd... I've never seen the Windows 98/ME compatibility on any of my GOG games...
Well, my first thought would be that if AVG's giving you virus warnings, you might actually have some viruses running around. Sometimes, they'll even attach themselves to EXE files which is why it might be triggering on OW. I'd do a full system scan and get it to disinfect or delete whatever it finds. If it does delete OW, get a new download of it and see if that works.
If it still doesn't work and it still has the Windows 98/ME compatibility thing, try renaming owar.exe to something else. Sometimes, when Windows tries to lock options like that by looking for the specific filenames. Change the filename and it might let you change the options. If that doesn't work, try making a copy of the file and use the copy instead.
EDIT: Oh yeah, and check to see if you might have any conflicts with any new software you've installed in the past few weeks since you last played OW and had it working.

Thanks for the reply.
I had already performed a full scan and 'healed' the infected files but it still didn't work. I assume these are only false positives because a brand new installation of OW and a new patch download triggered the same warning.
Making a copy of Owar.exe does indeed allow me to change compatibility settings, but the same problem persists.
The only system-level piece of software that I have installed lately would be the latest nVidia drivers. I can't think of anything else but I'll check to see if that's the perpetrator.
I forgot to mention that I'm running XP btw.
P.S. The virus threat I'm getting with OwarDedicated.exe and OwarFull.DLL are called
"Trojan horse Generic11.AMNM"

Some Anti-Virus applications will flag owarfull.dll and owardedicated.exe as trojans based on there Huristics. They are actualy just detecting that the application has a built in IRC client.

I just gave it a try again and it looks like it was just AVG automatically healing the file despite what I said.
I couldn't close down the AVG processes without having them restart themselves (security measure) so I did the second best thing and added the Original War directory to the resident shield exceptions prior to installing it. Works like a charm now.