The minidump file is not crashing your PC, it's a memory dump that can be used to diagnose what happened. Analyzing those is a specialist technique. A couple of points:
- A Minidump is like the name says: mini, as in small, and limited. If you're really having problems, you can enable full dumps, but there's no point doing anything with dumps unless you can analyze them, or get them to someone who can.
- However, you might get a better result by just checking out the STOP code and any other details you see.
- Silly question time: what changed? Nothing? I don't believe you!
Things to try:
1) Set the machine to stop if it happens, and not reboot immediately. This will give you time to check out the blue screen. In particular, you'll want to note the name of any files listed on screen - if it looks like a driver, that's likely to be the problem.
right-click on My Computer, select "Properties" On the "Advanced" tab, select "Settings" under "Startup & Recovery". Uncheck the box that says "Automatically reboot"
2) Look in the System Event Log for evidence of previous crashes, and see if Microsoft can provide any advice on them.
Open Control Panel - Administrative Tools - Event Viewer.
Select System, and look for any entries with Source = "Save Dump". (Use View - Filter if it helps). Open up one of those, make a note of the STOP Code it includes. Also, if there is a link after "For more information, see Help and Support Center...", try it. This sends the information to the Microsoft Knowledge Base site, and it will report anything it finds.
The System Event Log will report anything else it finds - if you want to learn how to fix problems with your system, you'd better get used to using it. The timing of entries can tell you lot: if you have a problem, check the log for entries on and around that time.