How many 7200 RPM SATA of faster disks do you use? What are the specs of that Toshiba?
I can find specs on Toshiba 2010 models that are far below minimum requirements, and some that, with major enhancements, approach something barely decent.
Windows 7 is a pretty stable and robust operating system. If a program is able to actually freeze Windows forcing a reboot, that's a pretty good indication that something is wrong with your Windows install. It might be time to start thinking about wiping the system drive and reinstalling everything from the ground up.
Google indicates that is a laptop... for which you need... read below
Some ideas for a Laptop Video Editing PC from past discussions
-NOTE only 1 hard drive in above, so you will need to add a 2nd drive or use eSata for video files
-or Google "ASUS G74SX-BBK7" (without the quote "" marks)
For effective HD video editing, a laptop with the following
-the newer Intel sandy bridge 2720 or 2820 quad processor
-and nvidia graphics preferably the 460m, 485m is a bit much
-1280x900 display with OpenGL 2.0-compatible graphics card
-and 8 or 16 gig ram and Win7 64bit Pro
-and 2 internal 7200 HDDs minimum
About 60GB of footage (not bringing it all in at once, in small groups)
I'm going to add to the list of possibilities corrupt media. If everything is working fine, and then stops or freezes anything, that's a piece of evidence.
Keep bringing in your footage, in smaller groups. Let it conform and save your Project before you bring in another batch. If it freezes again, next time, skip that group of clips. Get the rest of your footage in, and then go back to that 'problem group," and import your clips one at a time. If you find one or a few that freeze your computer, learn to live without them. Or, transcode them in another app to a different codec, before bringing them into Pr again.