Suddenly since today, my laptop welcomes for an hour before finally opening up the window.
Any one has any idea why it might be doing so?

what do you mean by 'laptop welcomes for about an hour'? 
- It boots and sits there for an hour in black screen and finally shows up Windows Screen/Desktop?? 
or what?? 

Try to revert back to some working previous date using Windows Restore Tool found at Start>Accessories>System Tools>System Restore

 Is it a HP? if it is your laptop is on its way out. Its the problem with the graphic chip because of heat. Also try taking out ram and reinstall them again, sometimes they just decide not to work properly.

anyone reading this probably should invest in good laptop cooler, like mine is CM STORM and it's the best to save your investment. But I know many don't know and don't really care and end up having situations like these.

Is this a right to thank Steve JObs??

It is a HP Laptop and I am having terrible heat issue. Sometimes it is so bad that it shuts down every 5 mins. I have been using this laptop for 5&1/2 yrs.
One day I was so frustrated that I disected the laptop entirely, separated every pieces of the laptop. Luckily I was able to put back the pieces together to get it running. Still the heat issue was not fixed.
Now I am thinking of turning off the heat sensor if there is one, I guess there must be. I have to do a little research on this.

I am also thinking of buying a cheap but durable laptop because I use it just for watching netflix and reading news, nothing else. Which laptop do you guys suggest? I am not buying tablets.

 This is the cheapest i3 i found for you, its new and will be enough for your needs. its $289 btw. Time to let that old computer go. 
http://www.newegg.com/Product/Product.aspx?Item=N82E16834200483&Tpk=N82E16834200483

 This one is a bit expensive, but its a lenovo. at 449
http://www.newegg.com/Product/Product.aspx?Item=N82E16834246483

 Here's a video on Hp heat sink mod:
https://www.youtube.com/watch?v=t9w-khwIj3U&feature=related

lol , i 'm also victim of HP dv 9000  after i used it for 2 years , then came to find out that dv 6000 and 9000 series all have problems,my went to the  black screen ,then i disassembled ,bought heat gun and thermal paste ,and heated nvidia microchip for 3 minutes to melt solder  then applied thermal paste and penny also and still didn't work and finally i threw it ,many of them works for sometime after applying heat on gpu to melt the solders  .It's the design flaw from HP and they faced lawsuit also ,i will never buy anything that's HP .

i barely know people running HP without heat problems!! i always advise people not to buy HP!! major heat issues!!

I agree with Alece. 
Their BGA chipset sucks. 
ANd those HP support trolls will always try to get you new computer replaced instead of troubleshooting. They're salesmen disguised as support technicians. HP didn't lose their PC market just like that. There are reasons for that we know it all :D 

Thanks guys.
@maxpayne: I will be buying that Lenovo next weekend.

This was on dealnews. But you have to upgrade to 4 gb ram minimal.

Dell Inspiron 11z Core i3 Dual 1.2GHz 12" Laptop