Hello all, I've been having this quite odd error with this game where every no and there I'd get a Windows warning message telling me that "There is no disk in the drive. Please insert a disk into drive \Device\Harddisk\DR1". This doesn't actually crash the game; upon pressing any of the buttons on the error message another two displaying the same message again and then I can just continue on playing the game..until I get it again at some seemingly arbitrary point.

This appear a lot of different areas in the game, but does not seem to happen until I get further into the main story (I've yet to play any of the DLC apart from Anchorage and that didn't seem to give me a problem to my recollection), There happened quite a lot with the quest to wipe out some of the Enclave after going through the car tunnel, but again it happens in lots of different world cells.

This is a modded game however I can't imagine why that would be a problem and more to a point this is the legitimate Steam GOTY version. It's location on the HDD is through the default Steam location (Programs (x86), maybe that could be the problem? I have heard FO3 doesn't like being localised through that path.

Any help would be much appreciated, thanks for reading.

That is your problem. See this for the proper install location, and the other tweaks you need to get the game running

http://www.gamesas.com/topic/1465357-installing-fallout-3-with-windows-78-and-xp/

Awesome, don't suppose fixing the solution would be as simple as a ctrl c, ctrl v on the Fallout 3 GOTY file over to the new location....would it?

Moving the Steam Directory is pretty easy. Almost as easy as you described above. See the page for a link on how to do that.

Wonderful, thank you very much for your help.