Hi Telstar
I've found another signal generator. No sweep function on the free version of this one but it will save wav files.
http://www.dr-jordan-design.de/signalgen.htm
A single executable no installation and it worked first time on my pc.
It appears to offer lots of functions but they are only available on the paid for pro version.
The free version does sine, triangular and square waves at any audio frequency set by numerical input or with a slider. Saving wav files you can certainly save single frequency sine waves of a defined frequency and duration, I haven't worked out if you can save a wav of a manual sweep.
Hope this is useful
Ray