Sony Vaio restarts by itself  

I have Sony Vaio VPCEB1S1E for 1 mounts, I bought it with windows 7 home premium 64 bit, I change it to Ultimate 64 bit, and during this one mount it restart by itself twice, different times and as I remember it happened because I used "WEB" button on my laptop (usually I am not using it), but when I am pushing it now it is not restarting anymore, I don't know if this is the reason?! The restarting looks like this:
Screen turning to gray color and it's just simply restarting, after it is ON, on my screen is appearing message, saying something like: "you system was recovered after an expected restart". If anybody familiar with this problem or just have a clue, PLEAS HELP ME

Thenk's

Hey WalkerA WinTeam (thank's for responding)
Yes! exactly the (WEB) button between (ASSIST) and (VAIO) buttons, but as I already mention it, I am not sure about it if that cause the restart, as I remember that restarts happens when I used (WEB) button (usually I am not using it), and the thing is that it doesn't restart immediately in a first tim I pushed, I pushed it many times, and then it happened, that's whey I am not sure, but when it happened, 2nd time, I remembered that first time it happened, also when I used that (WEB) button, so this is the situation, and I am really hoping that that's the reason and it is a kind of driver conflict problem, but not hardware!!!

Hey WalkerA WinTeam
Yes exactly! WEB button is for starting a browser, I don't know what ales can cause the problem, because it is new laptop and nothing dangerous happened with that laptop, as I already mention a bow I just reinstall the OS. Was Win 7 Home premium I change to Win 7 Ultimate, I install all drivers from VAIO support site, and actually I am not a dummy in "this business" :) And i am thinking it can be kind of driver problem, because that kind of things happening on windows "you know" unexpected restart ......!!! So thank's ones more for replying :)

Hear I coped the description of the problem, is there anybody that can tell me what is this about?
Problem signature:
Problem Event Name: BlueScreen
OS Version: 6.1.7600.2.0.0.256.1
Locale ID: 1033

Additional information about the problem:
BCCode: c2
BCP1: 0000000000000007
BCP2: 0000000000001097
BCP3: 0000000000000000
BCP4: FFFFFA8003FC4E00
OS Version: 6_1_7600
Service Pack: 0_0
Product: 256_1

Files that help describe the problem:
C:\Windows\Minidump\061310-20124-01.dmp
C:\Users\Haik\AppData\Local\Temp\WER-44257-0.sysdata.xml

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Thanks'