OS problem or Hard drive failing??

goku1234567890

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I have a problem, if i run my PC straight for 8 to 12 hours than the windows start hanging. Now i first thought is was due to the HDD being too hot over time so i opened the case and monitored the temperatures now they are not above 42C, recently they were at 50C to 54C. Windows again hang so it is OS right or the hard drive is failing?
 
If idle 50C is a little high, but under load it is nothing to worry over

If windows is sluggish I would look at CPU and memory usage in task manager to see if anything is eating up resources. You may have an infection, an application that just starts eating resources, or might just need some system maint. How old is the computer?
 

goku1234567890

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It is not that old and it is doing that at idle and i have already checked the task manager. I just installed Windows 8.1 Pro 1 or 2 month ago. Although i have to check for infection but i have only MSE or Windows Defender that came with Windows 8.1. And i checked the hard drive through Crystal Disk Info and i have reallocated sector count error or yellow mark. Current: 100, Worst: 100, Threshold: 11.