How can I reduce the size of SYSTEM.DAT

I have discovered, through experience, that once SYSTEM.DAT exceeds 1/4 ot real RAM then POW!! Windows fails to start. missing files like VXD etc.

I have tried Microsoft Regclean .. No
I have tried CleanReg .. Better than above but fails to freespace

Anyone out there who has a utility that can reduce the size of my System.Dat is worth their weight in gold.

For attached files pls send to

alan.robinson@rcss.uk.com

Thanks for reading this

Alan