Windows hangs/shuts down/BSOD in 10 mins

I have win7 home premium 64bit on my laptop. My laptop starts up, works fine, but in less than 10 minutes, it hangs up. Here are some details.
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One day, for some reason, I changed my power saving limits. I put "screen dim after ", "screen off after ", and "sleep after" ALL = NEVER.
Laptop went into "blue screen of death/BSOD ".
On startup, windows firewall is OFF, Kaspersky Internet Security is turned off, with "license key error" and "databases are corrupted" errors.

At that point, I restored system to a few weeks old restore point. That was only restore point I had in system.

On startup, Kaspersky could connect to internet and with updates, it began working.

But from that point onwards, my laptop starts fine, begins to run ok. But slowly begins to slow down, ultimately hangs/freezes/blue screen of death - usually in 10 minutes time.
When I start up next time, sometimes it starts fine,
> sometimes it goes into chkdisk.
>> Few times, it finds hard disk ok,
>> sometimes it finds many errors in harddisk, but is able to fix those errors and continue starting up.
> Some times my Kaspersky IS shows "Databases are corrupted" message. But after updating itself on internet, that message goes away. And it begins working normally.

But invariably, the laptop faces same fate - hangs/freezes/blue screen of death - in less than 10 minutes.

My BSOD message number is different, so I could not find a root cause.
I changed my power settings to normal values, but that did not help.
I have malwarebytes pro purchased version, no malwares detected.
I have Kaspersky Internet Security, no viruses detected.
I run rkill to kill any malware processes, but still problem continues.

Please help me. Without any help, I will have to reinstall or repair-install the OS once again, which will be big deal for me. Want to avoid that final resort.
I can run any reports or post event viewer logs etc if asked for. Expecting assistance, thanks in advance..