My laptop doesn't go into sleep mode anymore??

I'm not sure if this will work for you, but I'm 99% sure it is how i fixed my problem.
Open up your device manager, maximize "Network Adapters" and see if your PCI driver is signed.
I also had to download the latest update of the PCI driver from my laptops website. (i think the HP site for that is http://welcome.hp.com/country/us/en/support.html )

 

Oh my god!! It's fixed.. Thanks LDee! I had looked in my device manager lots but only was really looking for the yellow exclamation mark so when you suggested i click view and "show hidden devices" it made me look more closely at everything.. Anyway, under display adapters i had 2 items which looked exactly the same.. They were graphics controllers.. The top one had a really small red x on it. I had noticed this before but because the graphics controller underneath was exactly the same with no red x i just ignored it.. I feel a complete idiot now. When i opened both of them one said function 0 and one said function 1. So i enabled the one that was disabled then i was prompted to install new hardware and restart.. Then hey presto all my standby functions are back i even have a hibernate tab in my power management. I am so sorry for being so stupid. Thanks to everyone for their help.. Especially LDee.

 

I'm very glad it's finally fixed. Don't apologize, how would you have known you should have checked the hidden devices too? We should have thought of that sooner to be honest so I've learned a lesson.