windows 7 stops working

I have windows 7 home premium running (64 bit SP1) on a dell 1555 laptop. I have started getting a windows explorer has stopped working message. The machine freezes for about 5 minutes before this happens. If I click on restart program it restarts and generally runs ok after that. Then after the next resart it does the same again. No major changes or installs made recently.

I used ccleaner to disable start up programs that Ii dont need but it still happens.

Any ideas what I can do to fix it?

Thanks

 

Have you run a disk check, or tried a system restore to right before the problem started ??