I'm a bit mystified by these sorts of posts as I'm using Vista x64 and have no difficulties whatsoever - normally x64 is unhappy with everything.
Aside from the usual rather lame suggestions like "check your soundcard", try turning off all the Record Control Options (under 'Advanced Control Settings') - Auto-Start, Auto-Trim, and Voice-Activation. This, at the very least, makes it easier to check whether the record-clock is running when testing.
I have noticed that the record button kind of "sticks" from time to time (rather like a real deck), so try clicking the 'Stop' button first, then 'Record'.
I'm using an Asus Xonar D2 sound card (the one with all the christmas lights), so any suggestions about what 'Device' to set would be impractical, though you could try setting the Device to Stereo Mix and the 'Input' to Windows Record Mixer. This records whatever is playing on the speakers at the time so it's easier to test.
And remember that you won't see a wave representation of the sound until you end the recording, so the clock-count is all you have to go by.
And just for the hell of it: Check your soundcard.
Drivers, cables, et cetera.