AV Master - Getting Up-Grade to work

I've had an AV Master for about 3 years. It never has worked and the computer supplier is now out of business. I want to use it as a hobby.
As a last resort decided to up-grade my computer to Win98SE, AMD Athlon XP1600,256DDR memory,60Gb x 7200HD,ATI 3D Rage Pro PCI x 8Mb graphics Card.
All the recommended drivers have been downloaded from the Dazzle site for Fastcap Vs5.2-24 for win98Se including 6.0.0.2 patch.
With the aid of an experienced computer engineer (but not with video experience) all the set procedures and settings have been followed and double checked.
Result is that Vidcap will capture,but when I turn the overlay feature on, it will sometimes play back and sometimes not. In ULead 6.0, if I use the overlay feature it will just cease the computer up everytime I click on the Timeline Preview. It frequently ceases up even without the Overlay switched on.
Does anybody have any suggestions to solve this - Better still - Is there anybody out there who lives reasonably close to Biggleswade in Bedfordshire who I could bring the computer to and get it set up and working. You can e-mail me direct, if you can help.