Trouble with old DVR and new PC: Can control DVR with Video Server S, but no video

[Frank H]

Hi,
I've got an old (maybe seven or more years) 4CH DVR (unbranded model 771-A) and an equally aged Video Web Server (unbranded 732S). They've been in storage for the last four years but I dusted them down and everything seems to work OK. I can see the DVR direct on the TV monitor. When I installed Video Server S on my Win7 IE8 PC it installed fine and runs and I can control the menu and the cameras through the Video Server S software BUT I can't see any video at all. Same thing if I run the browser based DVR controller, the buttons all work and 'push' the buttons on the DVR but there is no video.
What have I missed out with my setup?
Thanks

[Frank H]

In addition I have dug out my old (10 years old) Windows 2000 laptop. Video Web Server definitely used to work OK on this poor old thing and now it doesn't, same problem DVR commands work - no video.
I'm beginning to lean towards either my router/modem is the video blocker, but that's all on the LAN side so I don't see that it should really be the problem, or it's the actual Video Web Server hardware that's at fault (although all it's two indicator lights are flashing in "I'm OK" sequence).
Any thoughts where I should look next?

[Frank H]

More Information...
I have connected to another Windows 7 IE8 laptop using a crossover cable and again the DVR controls work but still no video. Seems to me that this test rules out the Router as being part of the problem.
I'm reduced to either the 732s box having a fault or there is an IE8/ActiveX issue going on.