Vista RC1 Freezing issue

Hi all

I have been using the BETA version of Windows Vista since it we released to
the masses for testing and have just installed RC1 on my main system.

The problem i have is after a few minutes of using the OS it just freezes no
mouse movement, no nothing! I never had any problems with BETA 2 it ran
fairly well for its spec.

My systems spec is :-

Pentium 4 3.0ghz HT (Prescott core)
512MB DDR(PC2700) RAM
140Gb Primary HDD
80Gb Secondary HDD
ATI Radeon 9550 128MB
2x sony Dual Layer DVD re-writers

I think the problem may be the lack of memory but it ran BETA 2 well enough
so i'm at a loss to what it could be.

Any help would be greatly appreciated?!

Paul Hayward