Windows explorer not responding, fan on back of PC now buzzing for the first 2 minutes of start up

[Snostorm8]

Windows explorer will randomly start not responding, also suddenly the fan on the back of the PC has started buzzing for the first 2 minutes of start up.
I have to hard reset my PC once explorer stops responding
Also start up times have drastically increased recently.

I5 3570k no OC
8Gb Ram
Asus pb87z mobo
GTX 970
SSD used for windows
HDD used for programs
Win 8.1

Edit: Steam also has suddenly gone much slower than normal, performance in games is still fine though.

 

[rgd1101]

SSD is full? check disk on the HDD?

 

[Snostorm8]

SSD is full? check disk on the HDD?

80GB free on SSD 481GB free on the HDD
defragmented every week.
Hard drives are 2 1/2 years old, no issues before now

 

[reedo_43]

You aren't defraging the ssd are you?

 

[Snostorm8]

No only the HDD

 

[Snostorm8]

bump