Pelikal,
I assume you've tried installing/running the Microtek software in comparability mode ?
Whilst in certain scenarios stubbornness and persistence can be admirable... one does wonder why you're bothering fighting when you can pick up a brand new, current model scanner with comparable specs to your vintage Microtek for £40 !
Your Microtek 4900 was 2400dpi .... that's cheap entry-level these days.... if we go bottom fishing for the cheapest stuff on the market, the Canon CanoScan LiDE 120, HP ScanJet 200 and HP ScanJet 300 are all less than £50 and will all probably be equivalent or better than your old Microtek in terms of specs.
Nudge up to sub-£60 and you've got the Epson Perfection V37 which is double the resolution of your Microtek !
Last edited by mixture; 12th Nov 2014 at 16:31.